"In the thousands of people who were there peacefully, two guys who had weapons brandished them menacingly. They were both killed," the official said, insisting on anonymity.

The official said that the head of the US Central Command, General Kenneth McKenzie, told Taliban officials in a face-to-face meeting Sunday in Doha not to attack the airport.

Thousands of American troops took control of security at Afghanistan's main international airport outside Kabul on Saturday to enable the evacuations of US officials.

Afghans meanwhile massed at the airport and flooded out onto the tarmac seeking to board commerical flights out of the country.

Videos showed hundreds trying to impede the takeoff of a US military transport, and there were reports that several were killed, either being crushed or falling from it after it took off.