Crowds of people show their documents to US troops outside the airport in Kabul, Afghanistan August 26, 2021. (Photo:REUTERS/Stringer)

Islamic State (ISIS), an enemy of the Taliban as well as the West, said one of its suicide bombers targeted "translators and collaborators with the American army".

General Frank McKenzie, head of US Central Command, said US commanders were on alert for more attacks by Islamic State, including possibly rockets or vehicle-borne bombs targeting the airport.

He said that some intelligence is being shared with the Taliban and that he believed "some attacks have been thwarted by them."  

President Joe Biden said he has ordered the Pentagon to plan how to strike ISIS-K, the Islamic State affiliate that claimed responsibility.

“We will hunt you down and make you pay,” Biden said during televised comments from the White House.