A timeline of conflict on the Israel-Lebanon border

Lebanon joins other Arab countries, allied with Palestinian factions, in fighting Israel after it declared independence in 1948. The United Nations brokers two ceasefires during the conflict, but fighting continued into 1949, when Lebanon and Israel signed a general armistice agreement.

At the war’s end, Israel gains control over new territory and an estimated 700,000 Palestinians are displaced in what is known in Arabic as the Nakba, or the catastrophe — including about 100,000 people who flee to Lebanon, where some refugee camps remain.

Two members of the Palestine Liberation Organization, a guerrilla group, attack an El Al flight en route from Tel Aviv, during a layover in Greece, killing a passenger. Israel retaliates by raiding the Beirut International Airport and destroying about a dozen Lebanese passenger aircraft. The United Nations Security Council censure Israel for the military action.

Much of the PLO moves to Lebanon after it is expelled from Jordan.

As the state crumbled, a bloody, multifaceted 15-year civil war breaks out in Lebanon, devastating cities and leaving an estimated 120,000 people dead. Among the reasons for the instability, historians say, is domestic discord over whether to allow Palestinian militants to stage attacks against Israel from Lebanese soil.

Israel invades and occupies southern Lebanon in Operation Litani, after PLO guerrilla militants “infiltrated Israel from Lebanon by sea,” the IDF says, and attacked a bus, killing 35 people.

The conflict led the U.N. Security Council to establish UNIFIL, the U.N. peacekeeping force in Lebanon, to secure Israeli withdrawal from Lebanon.

Israel invades Lebanon in June 1982, in the midst of the civil war. Its stated aim is to “put the communities of northern Israel out of reach of the terrorists in southern Lebanon by pushing the latter 40 km to the north.”

Israeli forces occupy the south of the country and besieged West Beirut for several months, forcing PLO fighters there to leave Lebanon.

As Israeli forces take over West Beirut in September 1982, they allow Lebanese Christian militiamen under their political and military control to enter the refugee camps of Sabra and Shatila, where they kill hundreds or as many as several thousand unarmed Palestinian civilians — a massacre the memory of which continues to shape regional affairs. The U.N. General Assembly declared it an act of genocide.

Israel withdrew from West Beirut in late September 1982 but remained as an occupying force in the south of the country.

Hezbollah, a Lebanese Shiite militant group and political force, is established in 1982. In 1985, the group publishes a manifesto codifying its call for the destruction of Israel as a goal.

The civil war ends in 1990, but it is another decade before Israeli forces withdrew from the south of Lebanon, following 22 years of occupation.

Hezbollah and Israeli forces fight skirmishes in the summer of 2006. But the full-scale war that follows takes “everyone by surprise,” a member of the U.N. peacekeeping mission there later recalls.

On July 12, Hezbollah launches rockets toward Israeli military positions and border villages, as other Hezbollah militants cross into Israel, killing eight Israeli soldiers and capturing two others.

The next day, Israel begins attacking its northern neighbor by land, sea and air. Over the course of the month-long war that follows, Hezbollah launches nearly 4,000 missiles into Israel, according to the IDF.

In Lebanon, the month-long war kills about 1,200 people — the majority of whom were civilians — injured thousands more and forced around a million people to flee their homes, according to Human Rights Watch. According to the IDF, 49 Israeli civilians and 121 soldiers are killed.

A U.N. commission finds that the Israeli military demonstrated a “significant pattern of excessive, indiscriminate and disproportionate use of force” against civilians.

Both sides claimed victory in the 2006 war, but neither won, as The Washington Post reported a decade later.

After 2006, Israel appears to pursue an approach somewhat infamously described by strategists as “mowing the grass,” a metaphor for the idea that Israel cannot “permanently unroot and eliminate the entirety of Hezbollah,” but will instead “keep knocking it down so that it does not pose a significant threat to Israel and Israeli citizens,” said Jonathan Panikoff, director of the Scowcroft Middle East Security Initiative at the Atlantic Council’s Middle East Program. The same approach has been evident in rounds of conflict with Hamas in Gaza, until the dynamic changes with the Oct. 7 attack.

Lebanon itself suffers a devastating economic crisis that leads to rising levels of poverty, and a massive explosion in Beirut’s port caused by improperly stored chemicals sparks widespread over corruption and mismanagement.

On Oct. 8, 2023, a day after its ally Hamas carries out its deadly attack on Israel, Hezbollah launches strikes of its own. In the months that follows, the two sides exchange frequent fire across the border.

The conflict escalates, including with the assassination of a senior Hamas leader in the Lebanese capital in January and the assassinations of several senior Hezbollah commanders that follow.

But in mid-September, fears of a wider war peak as thousands of electrical devices explode in a suspected Israeli attack against Hezbollah inside Lebanon, killing at least 37 people, including children, and injuring thousands more. Hezbollah leader Hasan Nasrallah blames Israel for what he describes as an “act of war” and vows to respond.

The same week, Israel carries out some of the most intense cross-border strikes since Oct. 7, while dozens of people are killed in a strike against a senior Hezbollah commander in a Beirut suburb.

Israeli strikes on Monday kill at least 558 people and wounded at least 1,835, according to Lebanon’s Health Ministry.

Some 67,500 people have evacuated homes in northern Israel since October amid cross-border exchanges of strikes, according to the Taub Center, a research group. The fighting has uprooted about 110,000 people in southern Lebanon, according to the United Nations — a figure that does not reflect the latest round of displacement.