The Kabul airport attack, which killed 13 U.S. troops and at least 79 Afghans, was claimed by Islamic State militants. The Islamic State's Afghan affiliate, ISIS-Khorosan, has emerged as an enemy of both the West and of the Taliban.
The attack marked the first U.S. military casualties in Afghanistan since February 2020 and represented the deadliest incident for American troops there in a decade.
U.S. General Frank McKenzie, the head of U.S. Central Command, had said on Thursday that initial information was that two suicide bombers had attacked the airport gate and the nearby Baron hotel.
"I can confirm for you that we do not believe that there was a second explosion at or near the Baron Hotel, that it was one suicide bomber," Army Major General William Taylor told reporters on Friday.
He said U.S. troops wounded in the attack were now being treated in Germany.
Pentagon spokesman John Kirby told the reporters during the same briefing that the United States believed there are still "specific, credible" threats against the airport.
"We certainly are prepared and would expect future attempts," Kirby said, adding: "We're monitoring these threats, very, very specifically, virtually in real time."