Russian diplomat says US didn’t pass along ‘concrete’ info before attack

"Nothing was passed," Ambassador to the United States Anatoly Antonov told Russian state news agency TASS while answering a question about whether any information was handed over by the US side before the terrorist act.

He added, "No concrete information, nothing was transferred to us."

A U.S. State Department official said Saturday that the U.S. government had shared information on a possible attack with Russian authorities in accordance with its longstanding "duty to warn" policy.

That information sharing came ahead of Friday's deadly attack on a Moscow venue, during which at least 133 were killed, Russian investigators said. The search for bodies under the rubble of the complex continued on Saturday.

Antonov described the official Washington reaction to the attack on Friday as "rather muffled," adding that the administration followed on Saturday with a "clear" statement. But it was unclear how much information Washington officials had passed on prior to the attack, he said.

"The question arises whether U.S. officials passed all the available information to the Russian side, as they state," the ambassador said.

ABC News' Shannon K. Crawford contributed to this story.