Biden shows solidarity with Israel in audacious wartime visit.

Ms. Shani, 47, said she woke that day at around 6 a.m. to the sound of a ruckus outside the home she shares with her four children. Her 18-year-old daughter had stayed at a friend’s house the night before, but she gathered her two younger daughters, ages 12 and 9, and brought them into Amit’s bedroom, which was the house’s designated safe room.

These sort of events — disruptions that cause the family to seek shelter — are not unusual, and retreats to the safe room are usually precautionary and brief. Ms. Shani was not particularly worried.

Then she looked at her phone.

Her WhatsApp group chat with other mothers on the kibbutz was alarming. “Moms started to text what’s happening,” she said. “‘Help us.’ ‘They’re here.’ ‘They’re coming for every house in the kibbutz.’ ‘The house is on fire.’ ‘We can’t breath.’”

Ms. Shani texted her ex-husband, who also lives on the kibbutz. “His house was burned,” she said. “He messaged me that he could not breathe: ‘Please send someone here, please tell the kids I love them.’”

Panicked, she texted the woman in charge of kibbutz security. “She answered me: ‘I have no one to send.’”

Ms. Shani kept her eyes glued to WhatsApp. The terrorists were “all over the kibbutz and going house by house by house, doing what they want,” she said. “Killing, kidnapping, burning it down.”

Just after noon, she said, about half a dozen Hamas gunmen entered their house and broke the door of the safe room. “My son was trying to resist,” she said. “I said, ‘Don’t! Don’t! We have only our hands and they have guns! They will shoot you!’”

The terrorists ordered the Shanis to leave the safe room as the house filled with smoke, she said. They were eventually marched down a road within the kibbutz. Amit and two other Israeli men from a nearby house were ordered into a car.

“I was begging and crying and begging to leave him alone and take me,” Ms. Shani said. One of the kidnappers, she said, raised his gun toward her.

The car disappeared, and Ms. Shani, her two young daughters and the women from the neighboring house were left behind, unsure what to do. Chaos was still unfolding around them — there were gunshots, and houses were on fire. They broke the window of a nearby home, she said, and climbed inside. By the door was a bag filled with weapons and what appeared to Ms. Shani to be “a rocket.” They tiptoed passed the bag and lay silently on the floor for about eight hours, amid the outside cacophony of gunfire and men yelling in Arabic.

“There was no water, there was no light,” she said. “It was very hot, and it was very hard to breathe. There was glass everywhere.”

She told her children to pull their shirts up over their faces to avoid breathing smoke.

The waiting felt endless, she said. “You almost lose faith.” Where, she wondered, was the Israeli army? “All the kibbutz is dying here, and no one is coming to help!”

At 10 p.m., she said, Hebrew-speaking soldiers came to the house. Because of the bag of weapons, she was fearful they would assume Hamas terrorists were hiding inside. She began to shout in Hebrew, “There are children in here, don’t shoot!”

The soldiers ushered them from the house. There were dead bodies strewn all over the kibbutz, burned and shot, she said. She covered her daughters’ eyes. They walked for about 15 minutes to a spot where kibbutz survivors were congregating.

“I don’t know how we survived it,” she said. “It’s like a nightmare movie.”

Nir Shani, her ex-husband and Amit’s father, survived as well. In the days since, they have been waiting for information about their son. On Friday, an Israeli army official reported that Amit was classified as kidnapped.

“It was a great relief for us because there are only two options,” Ms. Shani said, “dead or kidnapped.”

Mr. Biden, who met Prime Minister Benjamin Netanyahu and with some Israeli victims of the Oct. 7 Hamas attacks during the first wartime visit to Israel by an American president, said he understood the desire for vengeance. He said the killings of more than 1,300 Israelis by Hamas would be the equivalent of “fifteen 9/11s” in the United States.

“You can’t look at what has happened here to your mothers, your fathers, your grandparents, sons, daughters, children, even babies and not scream out for justice,” the president said. “Justice must be done.”

But he warned against making the same mistakes that the United States did by letting the “all-consuming rage” that Americans felt more than two decades ago drive bad decisions. While he was not specific, he presumably was referring to the invasion of Iraq, which he voted for and later came to regret.

“I know the choices are never clear or easy for the leadership,” Mr. Biden said. “There’s always a cost. But it requires being deliberate. It requires asking very hard questions. It requires clarity about the objectives and an honest assessment on whether the path you’re on will achieve those objectives.”

The timing of the president’s visit could hardly have been more precarious politically. After an all-night flight from Washington, Mr. Biden landed in a country traumatized by terrorism and girding for a protracted war against Hamas, putting himself at the center of a volatile conflict as rockets and recriminations volley back and forth with no end in sight.

Mr. Biden was determined to allow no daylight between himself and Israel, even as he pressed privately for the resumption of humanitarian aid to Gaza and stressed the importance of minimizing civilian casualties.

“I want you to know you’re not alone,” he said.

“Hamas committed atrocities that recall the worst ravages of ISIS, unleashing pure, unadulterated evil upon the world,” he added. “There’s no rationalizing, no excusing it, period.”

Mr. Biden said he would ask Congress later this week for “an unprecedented support package for Israel’s defense,” citing the need to keep Israel’s air defense systems supplied with ammunition. He did not take note of the Republican failure to select a speaker in the House, a situation that has frozen the institution’s ability to act on any legislation, including more foreign aid.

But even as Mr. Biden pledged ironclad support for Israel, the president’s meetings with Mr. Netanyahu and the Israeli war cabinet shared a split screen with broken bodies being pulled from the rubble of the decimated hospital. After Mr. Biden’s comments Wednesday morning, American officials issued an initial intelligence assessment of the incident, concluding that the damage was caused by Palestinian fighters.

Israel has said it was an errant rocket fired by Islamic Jihad, an extremist group aligned with Hamas, that caused the loss of life at the hospital. But with the region convulsing with anger and protests after the blast, it was unclear whether the American endorsement of Israel’s denial would do much to convince many in the Arab world.

“Based on what I’ve seen, it appears as though it was done by the other team, not you,” Mr. Biden said unprompted as he sat in a Tel Aviv hotel next to Mr. Netanyahu.

“But there’s a lot of people out there not sure,” Mr. Biden said, referring to skepticism in the Arab world. “So we’ve got a lot, we’ve got to overcome a lot of things.”

Mr. Biden said at another public session later in the day that he relied on a U.S. military evaluation in drawing his conclusion. Asked by a reporter what made him so sure it was not Israel, he said, “The data I was shown by my Defense Department.”

Mr. Biden also said Israeli officials he met with had agreed to his request that they allow food, water and medicine to be delivered to Palestinians in Gaza from Egypt in a humanitarian effort overseen by the United Nations and others.

But he warned Hamas against taking the humanitarian aid for its own survival.

“Let me be clear: If Hamas diverts or steals the assistance, they will have demonstrated once again that they have no concern for the welfare of the Palestinian people and the land,” he said. “As a practical matter, it will stop the international community from being able to provide this aid.”

Protesters threw rocks at security forces and smashed windows in Ramallah, one of the West Bank’s largest cities, on Tuesday night. Smaller protests broke out in many other areas. And in East Jerusalem, residents said that Israeli security forces battled with a crowd throwing rocks and Molotov cocktails and the rattle of gunfire echoed across the rooftops for hours.

By Wednesday morning, Palestinian leaders had called a general strike. Most people obeyed. Shops and schools were closed, streets were mostly deserted, and police trucks were cruising around. Many residents stayed indoors, though protesters continued to hold demonstrations into the evening. The Palestinian Authority’s health ministry reported that Israeli forces had shot and killed two people.

Although it remains unclear who was at fault for the enormous explosion at the Ahli Arab Hospital in Gaza on Tuesday, the overwhelming view among Palestinians was that it was an Israeli airstrike.

The Israeli claim that it was actually caused by a malfunctioning rocket fired by Islamic Jihad, a militant group within Gaza that works closely with Hamas, was widely dismissed. Neither claim has been independently verified.

“Israel is completely responsible for the attack,” said Hassan Froukh, a carpenter in Ramallah. “I can’t imagine why Islamic Jihad or Hamas would be interested in killing their own people.”

These thoughts were widely echoed across the Arab world. Like many others, Mr. Froukh believed that the imagery the Israeli military has cited, showing what it says is evidence of the strike by the malfunctioning Islamic Jihad rocket on the hospital, was fabricated.

Gazan officials have said hundreds died from the blast. No precise figure could be confirmed independently, but images from the hospital, which is run by the Anglican Church, and witness accounts made clear that many people had been injured and killed.

The West Bank is a mountainous territory populated mostly by Palestinians and occupied by Israel. The protesters here have been mainly venting their rage about fellow Palestinians killed in Gaza. But another theme has been intensifying this past week: fury at the Palestinian Authority.

Many residents consider the authority weak, corrupt and an Israeli puppet. On Wednesday, protesters demanded that the Palestinian Authority’s president, Mahmoud Abbas, resign. Protesters are also expressing pro-Hamas views. Hamas seized control of Gaza from the Palestinian Authority in 2007.

“Our authorities are collaborators,” protesters shouted. “Tomorrow Hamas will be here!” A co-founder of Hamas, Hassan Yousef, attended one of the protests.

In Deir Jarir, a Palestinian village northeast of Ramallah, youths attacked one of the authority’s security service buildings. Palestinian forces fired back from the rooftops. One Palestinian official, who asked to remain anonymous because he is not allowed to speak to journalists, said the security services had been given orders to protect themselves but to exercise restraint so as not to inflame things further.

Since the Oct. 7 attack on Israel, which killed more than 1,400 people, and Israel’s retaliatory strikes on Gaza, which have killed more than 2,700 Palestinians, tensions have been steadily rising in the West Bank. Security forces have clashed with gunmen and protesters, and the Palestinian authorities said that more than 50 people had been killed. Israeli security forces have also been making wide sweeps of many neighborhoods, arresting hundreds of suspected militants since the attack.

“There is a deep, direct connection between New York State and Israel that has always been there, a bond steeled over decades,” the governor, a Democrat, said in an interview at Kennedy Airport shortly before boarding a 10-hour commercial flight. “And it’s easy to go when the sun is shining and everything is fine.”

“The community feels, in Israel and in New York, that my going during these times will be the most significant symbol of their importance to us than anything else we could do,” she said.

Trips to Israel are nothing new for New York leaders, who routinely pay visits to make political statements aimed at Jewish New Yorkers. But the timing of Ms. Hochul’s visit — her first international trip since taking office in 2021 — is anything but routine.

The governor landed in Tel Aviv on Wednesday afternoon just as Israel was amassing troops outside Gaza, roughly a week after Hamas, a Palestinian militant group, killed over 1,400 Israelis in terror attacks that have profoundly shaken the country and drawn comparisons to 9/11.

Ms. Hochul’s presence — overlapping with President Biden’s trip there — may create an additional security headache for a country that already has too many.

But during her 30-hour “solidarity mission,” Ms. Hochul, a Democrat, is not currently scheduled to join the president. She was to meet with diplomats and local officials, and also console Israeli families that were displaced or impacted by the attacks. She is being accompanied by an entourage of state police officers and a clutch of top aides, including her press secretary, policy director and director of Jewish affairs, all of whom are Jewish.

Former Gov. David Paterson, a Democrat, said Ms. Hochul’s trip would help cement her positioning as an unflinching supporter of Israel, and that her role as a stateside governor with no sway over foreign policy was “not to be a negotiator, but to be a sympathizer.”

“I think there’s a rampant fear that Israel isn’t going to get the support that it deserves,” Mr. Paterson said in an interview. “And Governor Hochul hasn’t allowed herself to be portrayed as in any way being hesitant about her support.”

Yet Ms. Hochul’s visit comes at a sensitive moment for Democrats at home.

Democrats largely united in horror after Hamas’s deadly raid, mourning the Israeli dead while condemning the militant group in grave terms. But as Israeli counterstrikes accumulate and with a ground incursion into Gaza likely imminent, cracks appear to be surfacing once more within the party nationally and in New York over what comes next.

While Ms. Hochul and moderate Democrats affirm Israel’s right to defend itself on its own terms, progressive and far-left officials have urgently begun calling for a cease-fire and de-escalation of hostilities. Some of the loudest voices — including Representative Alexandria Ocasio-Cortez — come from New York.

Ms. Ocasio-Cortez was among a dozen Democrats to endorse a nonbinding House resolution urging the Biden administration to push for a cease-fire and to prioritize civilian lives. Two other New York House members, Nydia Velázquez and Jamaal Bowman, have also signed on. Ms. Ocasio-Cortez and Mr. Bowman have also declined to sign onto another competing resolution supported by the vast majority of both parties in Congress condemning the Hamas attack and reaffirming Israel’s right to fight back.

Some left-wing lawmakers like Assemblyman Zohran Mamdani, a democratic socialist from Queens who has also vocally supported a cease-fire, have cast Ms. Hochul’s trip as a ringing endorsement of Israel’s deadly strikes in Gaza. He called the trip “disgusting.”

“The killing of civilians should concern us all,” he said. “Yet for some reason, the deaths of Palestinians does not provoke the same outrage for the governor or, in her case, any outrage at all.”

Like other Democratic officials, Ms. Hochul has sometimes struggled to straddle the complicated line between forcefully defending Israel’s response and recognizing the high numbers of Palestinian casualties. Shortly before her trip, she held a media briefing where she addressed the explosion at a hospital in Gaza that left hundreds dead.

“We want to make sure that we acknowledge Israel has a right to defend itself against Hamas,” she said. “We also must make sure that civilians get humanitarian aid and lament the loss of any life of innocent civilians.”

After some critics suggested her comments were insensitive, her press team released a new statement mourning the loss of lives at the hospital, with the governor saying that she awaited “further information from the White House on the cause of this explosion.”

In the airport interview on Tuesday, Ms. Hochul echoed Mr. Biden’s calls for more humanitarian aid for Gaza and stressed the need to limit civilian casualties.

“Hamas is a terrorist organization; they only understand strength,” the governor said. “That does not mean that I’m not full of compassion for the innocent civilians who have lost their lives and are in harm’s way right now in Gaza. It’s not one or the other.”

The governor’s first visit to Israel — previously scheduled trips had been derailed by blizzards and wildfire smoke in New York — is expected to be mutually beneficial.

Ms. Hochul, a daughter of Catholic activists who said she traces her connection to Jewish culture back to interfaith gatherings her parents organized growing up, will get to send a strident signal to Jewish New Yorkers that she is on their side.

For the Israeli government, the special visit by a top-ranking American official, however symbolic, could help buttress the notion that an incursion into Gaza had international support.

“They understand the importance of having the most important governor in one of the most important Jewish communities in the country standing with their people,” said Steve Israel, a former Democratic congressman from Long Island, who is Jewish. “This is as big a bully pulpit as you’re going to get other than the White House.”

Nicholas Fandos contributed reporting from New York.

“There were hundreds of people in the streets, panicking and running,” Mr. Hammash, 31, said in a voice message that he managed to send in a rare moment of internet connection. “Whenever a rocket strikes, you don’t know where to go.”

The blare of ambulance sirens did not stop, Mr. Hammash said, and the city was bombed through the night.

He added: “I don’t think we can handle the situation much longer.”

Last week, Israel ordered all of Gaza’s northern residents — some 1.1 million people — to abandon their homes “for their own safety” and head south, ahead of an expected ground invasion of the strip. Hundreds of thousands obeyed, leaving by car and motorcycle and even on foot.

But despite its declarations, Israel on Tuesday intensified its bombings of the southern cities of Khan Younis and Rafah. It had already cut off Gaza’s water and electricity and imposed a “total siege,” refusing to allow any supplies to come into the blockaded territory.

On Wednesday, the situation grew even grimmer.

According to the International Committee of the Red Cross, three out of five wastewater plants in Gaza are no longer functioning, and two desalination plants were out of operation, leaving residents with no access to clean drinking water. There was a high risk of wastewater flooding, potentially creating a rise in the risk of disease outbreaks.

More than two million Gaza residents also struggled to communicate with the outside world — and with one another. Telecommunications towers destroyed by Israeli missiles and power outages meant that it was almost impossible to get online or make phone calls.

“We are disconnected,” said Mr. Hammash. “We don’t have internet, and even for the local phones, you have to keep on calling 30, 40 times just to check on your relatives and loved ones.”

And as the territory was running out of fuel to run backup generators, hospitals risked “turning into morgues,” the I.C.R.C. said. Not only were they overflowing with a record number of injured people, they were also increasingly being targeted by airstrikes.

The World Health Organization has recorded 51 attacks on health care infrastructure in Gaza since the violence erupted last week, and 15 health care workers killed while on duty in what the organization described as violations of international humanitarian law.

All that time, aid shipments were backing up at the Rafah border crossing between Egypt and the Gaza Strip, but it was not being allowed inside the blockaded territory. The I.C.R.C. said it had assembled 60 tons of medical items, and the W.H.O. said its shipments of medical supplies and equipment had been lined up at the border for the past three days. The European Union sent a humanitarian cargo flight with shelter, water, sanitation items and medicines to Egypt, with another one expected Thursday.

There was some reason for hope late Wednesday, when Israel said it would not block deliveries to Gaza from Egypt. There was no immediate comment from Egypt. But aid agencies warned that even if the aid gets in, there has to be a reassurance that it can be safely distributed throughout Gaza.

“There is an urgent need for fuel, food, water and, of course, medical supplies,” Dr. Richard Peeperkorn, the W.H.O. representative for the occupied Palestinian territory, said in a virtual news conference. “The supplies are ready, they are waiting at the border to be let in.”

He added: “This horror has to stop.”

Although Israel imports nearly all its oil, analysts said that such an embargo would probably have little immediate impact, because the country does not buy oil from major Persian Gulf producers like Saudi Arabia and the United Arab Emirates or Iran.

Instead, Kazakhstan, where oil is mostly produced by joint ventures involving Western companies including Chevron and Exxon Mobil, and Azerbaijan are among Israel’s biggest suppliers. Nigeria is also a substantial supplier.

But just raising the specter of an embargo conjured up memories of the ban on oil shipments initiated 50 years ago during the 1973 Arab-Israeli war. The embargo, imposed by Arab members of the Organization of the Petroleum Exporting Countries on the United States and some other countries for their support of Israel, led to long lines at gasoline pumps in the United States and higher oil prices that continue decades later.

Worries about a broad embargo seem partly responsible for sending prices for Brent crude oil, the international benchmark, up to about $93 a barrel, from $91.50, on Wednesday. Brent prices later eased back.

“People are mostly just afraid of what is there to come in the future,” said Viktor Katona, an analyst at Kpler, a firm that tracks petroleum shipments.

It would be a big leap for major producers like Saudi Arabia to follow Iran’s lead into some wider confrontation with the West. “There is no sign yet that other OPEC members would be on board or willing to join in such an action,” said Richard Bronze, head of geopolitics at Energy Aspects, a research firm.

But Israel could be vulnerable to damage to its ports or a cutoff in shipments. Aware of the risks, Israel appears to have been careful to maintain supplier relationships with diverse sources, Mr. Bronze said.

Already, one of its two major oil ports, Ashkelon, has at least temporarily stopped receiving oil, apparently for safety reasons, analysts said. Israel can still receive oil through another port at Haifa, north of Tel Aviv, although Mr. Katona said it had not received any fuel for more than a week. He added that Israel had at least a month’s supply of oil on hand in storage tanks.

A spokeswoman for the Israeli government said it would not comment about the port situation “at this time.”

Mr. Katona estimated that Israel imports about 270,000 barrels of oil a day, with about 90,000 barrels a day, or one third, coming from Kazakhstan and 50,000 barrels a day coming from Azerbaijan.

Kazakhstan and Azerbaijan have majority Muslim populations, but they are unlikely to join the Iranian foreign minister’s call for an embargo. They are not among the states in the Middle East like Jordan and Egypt, whose public closely monitors tensions between Israel and the Palestinian populations in the occupied West Bank and Gaza.

President Biden said on Wednesday that he had urged Israel to allow some humanitarian aid into Gaza and Israel said it would not block deliveries from Egypt, offering the first sign of relief to civilians in the enclave. There was no immediate comment from Egypt, where emergency supplies are waiting to cross through the key land border with Gaza.

Here is what to know about the Rafah crossing:

What does it look like?

On the Palestinian side, two giant arcing structures cross each other above a short building encased in stone, with ornate metal gates blocking the way. In recent days, people hoping to leave Gaza have waited near this area.

After passing through these gates, travelers encounter another Palestinian gate where their credentials are checked. Then they usually get on a bus to travel a few hundred yards to the Egyptian part of the crossing. Private vehicles are not allowed to pass.

1,000 feet

Crowds

waiting

at gate

EGYPT

GAZA

Strike

craters

Rafah

crossing

Gate

Additional fencing

Humanitarian aid

trucks waiting

along road

1,000 feet

Crowds

waiting

at gate

EGYPT

GAZA

Strike

craters

Rafah

crossing

Gate

Additional fencing

apparent on satellite

Humanitarian aid

trucks waiting

along road

On the Egyptian side is a wide structure with a yellow facade. Photos have shown aid workers parking their trucks by the gate on that side, waiting for a decision to be made on the opening of the crossing.

Why is Rafah important to Gaza?

Restrictions on the movement of people and goods to and from Gaza, imposed by both Israel and Egypt, have undermined the living conditions of Palestinians in the strip. Both Israel and Egypt have made entering from Gaza conditional on obtaining a permit from either government.

Egypt has at times kept the gate closed in response to security conditions. In 2022, the Rafah gate was open on 245 days, according to a United Nations report, which said that more than 133,000 people entered and 144,000 exited.

Goods such as diesel, cooking gas and construction materials normally pass through the nearby Salah a-Din gate, which started operating in 2018. Before that, said Tania Hary, the executive director of Gisha, an Israeli nonprofit organization that advocates for the free movement of Palestinians, household goods were mostly smuggled through underground tunnels.

How has Rafah been affected by the war?

According to the U.N. High Commissioner for Human Rights, the crossing has been damaged by Israel’s retaliatory airstrikes against Hamas, the armed Islamist group that controls Gaza. After analyzing videos and satellite imagery, The New York Times verified multiple strikes that hit close to the crossing.

On Monday, some foreign passport holders who were waiting at the border in hopes that it would open so they could leave Gaza said they were evacuated after the crossing was struck.

On Tuesday, U.S. officials said they hoped Israel would refrain from bombing the Rafah crossing area.

What is the situation now?

Hundreds of people have gathered in front of the gates on the Gaza side in recent days, following suggestions that foreign and dual citizens might be able to leave. But efforts by the United States and others to broker a deal with Israel and Egypt to allow foreigners citizens to leave and humanitarian aid to get in have so far failed to bear fruit, and the border has stayed closed.

Many American citizens in Gaza said they were staying in temporary accommodations near the border so they could be ready to cross in case it opened. Like most in Gaza, they have had to limit communications because it has been hard to find power to charge their phones, and they have struggled to find medicine, water and food.

At one point this week, guards on the Gaza side of the crossing were telling people it was closed, according to a Palestinian American who was hoping to cross. A Palestinian official said the guards were from the Hamas-run interior ministry.

Truckloads of aid from several countries have been waiting for the green light to cross into Gaza from Egypt. Photos and videos show lines of aid trucks idling as far away as the Egyptian city of Arish, about 30 miles from the border. On Wednesday, a World Health Organization official said the delays were the result of “finger pointing” and were “extremely frustrating.”

Iyad Abuheweila, Abu Bakr Bashir, Monika Pronczuk, Sarah Kerr and Ainara Tiefenthäler contributed reporting.

Opening the Rafah crossing to aid and keeping it open will be fraught, diplomats and officials warned, because of the high level of mistrust between Israel, Gaza and Egypt and the ever-present potential for flare-ups.

But aid is there, and more is on the way. The European Union paid for a cargo planeload that arrived at the small airport of El Arish on the northeastern coast of Egypt, near the Rafah crossing, on Tuesday. Another plane with EU-funded aid will depart Copenhagen for the same airport on Thursday.

But Egyptian authorities have not permitted European and U.S. diplomats to access the area, not even to inspect the aid their governments have sent, officials said. The lack of access reflects Egypt’s desire for tight control of the region, which is in a province where Egypt has fought militants for years. Egypt fears the Gaza conflict could spill over the border, sparking unrest within its borders.

In the meantime, 106 trucks loaded with aid from local charities have been lined up outside the gate at Rafah, awaiting the opening of the crossing. An additional 58 trucks with aid were delivered to the Egyptian Red Crescent in the city of Arish early Wednesday.

Storage facilities of the Egyptian Red Crescent are overflowing with humanitarian aid supplies, and the El Arish football stadium, which is storing aid sent from foreign countries and international humanitarian organizations, has also reached maximum capacity, a senior member of the Egyptian Red Crescent said.

Shortly after President Biden announced, and Israel confirmed, that aid into Gaza would not be blocked from Egypt, the convoys still sat silent and there were no signs of increased activity.

“While we continue to collect information, our current assessment, based on analysis of overhead imagery, intercepts and open-source information, is that Israel is not responsible for the explosion at the hospital in Gaza yesterday,” said Adrienne Watson, a spokeswoman for the National Security Council.

Other U.S. officials, who spoke on the condition of anonymity to discuss the sensitive information, cautioned that the analysis was preliminary and that they were continuing to collect and analyze evidence. Multiple officials said the evidence gathered so far refutes claims that Israeli forces were responsible for the blast and was strong enough for President Biden to make comments supporting Israel’s account of events.

“Based on what I’ve seen, it appears as though it was done by the other team, not you,” Mr. Biden told Prime Minister Benjamin Netanyahu of Israel during a joint appearance on his rare wartime visit to Israel. Mr. Biden said later that he had based his comments on an American military evaluation.

A senior Defense Department official said based on the launch data collected by infrared sensors that the United States was “fairly confident” the launch did not come from Israeli forces.

The Israel Defense Forces said that after a review, it found that a malfunctioning rocket fired by Palestinian Islamic Jihad caused the catastrophic blast at the Ahli Arab hospital. The group has denied the claim, and the Hamas-run Gazan health ministry said that an Israeli strike caused the blast, which it said killed hundreds of Palestinians.

On Tuesday, Israeli officials provided American intelligence agencies intercepted communications between Hamas members that indicated the rocket was fired by their side. Israeli officials have said the rocket was fired by Palestinian Islamic Jihad, a group allied with Hamas.

U.S. officials spent the night analyzing those intercepts along with the open-source data, videos captured by journalists and others that show a rocket flying in the vicinity of the hospital.

The United States regularly uses infrared satellite collection to analyze launches. The warning system was one of the first pieces of intelligence that showed that a Malaysia Airlines plane was shot down by Russian forces over Ukraine in 2014.

Other Republican senators echoed similar concerns this week, accusing Mr. Lew of having misrepresented parts of the multinational nuclear deal the Obama administration negotiated in 2015 when he testified about it in Congress. The deal eased sanctions on Tehran in exchange for the Iranian government abandoning its nuclear ambitions.

“I have some doubts, given his strong advocacy on the J.C.P.O.A., which wasn’t always accurate,” said Senator Dan Sullivan, Republican of Alaska, using an acronym for the nuclear deal. He added that Mr. Lew’s past positions on the Iran deal potentially disqualified him as an ambassador to Israel because “you can’t talk about Israel without talking about Iran.”

Since war between Israel and Hamas broke out more than a week ago, Republicans have accused the Biden administration of having pursued policies with Iran that allowed its ally Hamas, the group that has run the Gaza Strip since seizing power in 2007, to grow stronger.

While partisan squabbles often sprout up around high-profile ambassador nominees, the disputes over Mr. Lew’s nomination have alarmed Democrats, who argue that confirming him is a critical component of demonstrating that the United States stands with its ally Israel.

Leading Senate Democrats pushed back hard against the Republican accusations this week, defending Mr. Lew as the right person for the job.

“Mr. Lew has proven himself a strong public servant, a ferocious ally of Israel,” Senator Chuck Schumer, the majority leader, said on the floor on Tuesday. “Delaying him would be egregious at a time like this.”

Senator Ben Cardin, the chairman of the Foreign Relations Committee, which will consider Mr. Lew’s nomination, said in an interview that he thought the Republican opposition would not be widespread enough to keep him from becoming ambassador.

“I would think that Lew would have the support of enough to move him,” Mr. Cardin said, adding that he and Mr. Schumer would use whatever procedural tactics necessary to move Mr. Lew’s nomination out of committee and through the Senate floor.

“This is a priority,” he added.

But Republican lawmakers on the panel did not sound inclined to accelerate Mr. Lew’s nomination.

“I have real concerns that he has misled and lied to Congress in the past,” Senator Marco Rubio, Republican of Florida and a senior member of the Foreign Relations Committee, said on Fox Business. “We’ll go through those hearings. We’ll go through that process.”

In a press briefing on Wednesday morning, Rear Adm. Daniel Hagari, an Israeli military spokesman, said that Islamic Jihad fired 10 rockets at 6:59 p.m local time. One of the rockets, he said, fell to earth prematurely, hitting a parking lot outside the hospital. He said that Israel had not fired any ordnance in the area of the hospital at that time.

He cited a photograph of the parking lot that was posted on social media on Wednesday morning that he said did not show the kind of impact that would have been caused by an Israeli missile. The New York Times has not verified the photo. The photo shows the effects of a fire — burned-out cars and scorched ground. Admiral Hagari said that the damage was caused by rocket fuel that caught fire after hitting the ground.

He also showed aerial footage that he said was taken from a military drone overnight. In the images, he said, there was no evidence of a crater caused by an Israeli missile.

And he dismissed suggestions that the strike was caused by an errant Israeli air defense interceptor; he said Israel does not fire air defense missiles into Gazan airspace.

The admiral played a recording of what he said was a wiretapped conversation between two Hamas members, in which one speaker says the damage was caused by a rocket fired by Islamic Jihad from a cemetery near the hospital. The New York Times is assessing the material and has not verified the conversation.

Frustration in the Arab world and the wider region over the crisis in Gaza has been building and appeared to boil over after the blast, though it remained unclear who was responsible for it. Gazan health authorities said it had been caused by an Israeli airstrike, while the Israel Defense Forces said it was caused by a rocket fired by a Palestinian armed group that malfunctioned after launching. Neither assertion could be immediately verified.

In the Israel-occupied West Bank, Palestinians held mass demonstrations on Tuesday night into Wednesday morning in solidarity with Gaza. In Ramallah, protesters chanted slogans and marched to the headquarters of the Palestinian Authority — the internationally backed authority that holds limited autonomy over the West Bank.

As President Mahmoud Abbas, who is largely unpopular in the territory, landed by helicopter at the headquarters and entered shortly after midnight, many in the crowd attacked security forces with stones, glass bottles and metal objects. Security forces fired sound bombs and tear-gas canisters to break up the crowds.

In Jordan, which is home to more than two million Palestinian refugees and was hosting Secretary of State Antony J. Blinken on Tuesday night, protesters demonstrated in front of the Israeli embassy in the capital, Amman, and security forces deployed tear gas. There was also a protest march in Irbid, one of the country’s largest cities, the state news agency, Petra, reported.

Thousands turned out for demonstrations in cities across Turkey into the early hours of Wednesday morning, and there were reports of scattered clashes with police. In Istanbul, police pepper-sprayed protesters who attempted to storm the Israeli consulate with stones, sticks and fireworks, and five people were detained. One person at the scene had a heart attack and died, the governor’s office said, while many others, including police officers, were injured.

In the capital, Ankara, dozens of protesters gathered in front of the Israeli Embassy, reciting the Quran and praying for the dead. Police prevented some protesters from storming the building, according to the Demiroren news agency.

In Lebanon, where fighting on the border with Israel has intensified in recent days, protesters continued to rally in front of the French and U.S. Embassies early Wednesday morning. Lebanese security forces used tear gas on the crowds protesting at the U.S. Embassy, Reuters reported.

In Iran, the state news agency IRNA published video of protesters gathered in Tehran’s Palestine Square and waving Palestinian flags on Tuesday night in front of the French Embassy.

And in the normally sleepy city of Muscat, Oman, hundreds of Omanis and others took to the streets on Wednesday to protest Israel’s bombardment of Gaza, chanting “Occupier, get out of Palestine” in front of foreign embassies.

Crowds also gathered in Rabat, Morocco, and Tripoli, Libya, late on Tuesday night, waving Palestinian flags and holding up signs, as well as in Sana, the capital of Yemen. Hundreds also demonstrated in front of the French embassy in the Tunisian capital on Tuesday night, some demanding the expulsion of the French ambassador, Tunisian state media reported.

Euan Ward contributed reporting from Beirut, Lebanon; Fahad Al Mukrashi from Muscat, Oman; Vivian Nereim from Riyadh, Saudi Arabia; Rami N. Nazzal from Ramallah, West Bank; and Safak Timur from Istanbul.

“The United States is taking swift and decisive action to target Hamas’s financiers and facilitators following its brutal and unconscionable massacre of Israeli civilians, including children,” Treasury Secretary Janet L. Yellen said in a statement.

“We will continue to take all steps necessary to deny Hamas terrorists the ability to raise and use funds to carry out atrocities and terrorize the people of Israel,” she said.

In addition to targeting two senior Hamas members, the U.S. is also imposing sanctions on Hamas’s secret investment portfolio, which the group uses to obscure who controls its assets, and a virtual currency exchange that Hamas has used to raise and transfer funds.

U.S. sanctions can essentially freeze the assets of a person or organization and cut them off from the Western financial system.

Because Hamas is already heavily sanctioned, the Biden administration has been increasingly going after “financial facilitators” in countries such as Sudan, Turkey, Algeria and Qatar that help Hamas operate.

Wally Adeyemo, the deputy Treasury secretary, said on Wednesday that the United States was “committed to imposing more sanctions, alone and with our partners” on Hamas. He added that senior Treasury officials would be traveling to the Middle East and Europe in the coming days to coordinate with U.S. allies on ways to more effectively cut Hamas off from its money.

“There are still lots of bodies they haven’t yet collected,” said Amir Ahmed, a paramedic with the Palestinian Red Crescent in Gaza City. “There are too many bodies.” He said all the victims would be buried in a mass grave at a funeral later on Wednesday.

“There is a big possibility that they will just put a number” on the body bags without any names, Mr. Ahmed added, “because many are in pieces.”

Palestinian officials blamed the carnage on an Israeli airstrike, an assertion that was disputed by the Israel Defense Forces, which said it was caused by an errant rocket fired by an armed Palestinian faction in Gaza. Neither side’s account could be independently verified immediately, and the cause of the blast and the precise death toll remained unclear.

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Many of those killed at the hospital, which is run by the Episcopal Diocese of Jerusalem, were women and children, said Dr. Ashraf al-Qudra, a spokesman for the Health Ministry in Gaza. He said doctors in another hospital in Gaza City were now performing surgery on patients on the floor or in corridors, often without anesthetic.

“The sudden increase of hundreds of victims with complex injuries far exceeded the capabilities of medical crews and ambulances,” he said in a statement.

Many of the wounded could die because of a severe shortage of medical supplies, water and electricity. Israel has imposed a complete siege of Gaza since last week, cutting off food, water, electricity and fuel.

Since Israel’s intense bombardment of Gaza began on Oct. 7, in response to a surprise attack by Hamas that killed at least 1,400 in Israel, residents have found that nowhere is safe.

About half of Gaza’s population of more than two million Palestinians have fled their homes since the Israeli bombardment began, according to the United Nations. Many have sought shelter in the corridors and courtyards of hospitals, believing that they would be less vulnerable there.

Those wounded in Tuesday’s explosion were taken to other hospitals in the city, which were already overwhelmed after 11 days of Israeli airstrikes on the besieged coastal strip.

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The Palestinian journalist Motasem Mortaja captured a chaotic scene at one of those sites, Al Shifa Hospital, posting videos to social media of screaming children in bloodied clothing, women wailing in pain and men kneeling in prayer.

Hospital staff were treating the wounded wherever they could, rushing to bandage men lying on a floor red with their blood.

In one video, a young child lifts his shirt to reveal a wound to his chest. His hands, hair and clothes are dusty from the blast.

“I hope that this war ends soon,” Mr. Mortaja said in a voice memo sent Tuesday night to The Times. “We’ve never lived through a war this intense.”

Under a tent outside Al Shifa Hospital, where many of the dead and wounded were taken, workers lifted the dead from the blankets they were wrapped in and placed them in white body bags. In videos posted to Instagram and verified by The Times, other bodies lay exposed, and people walked past them in search of loved ones.

One man, standing over the bodies of two young boys, wailed in grief.

“I don’t have any more children. These were my only children,” he said.

Chevaz Clarke-Williams contributed production.