US President Joe Biden insisted that he would bring home American citizens stuck in Afghanistan after the Taliban took over Kabul but warned that the "difficult operation" was "not without risk of loss".
"Make no mistake: this evacuation mission is dangerous. It involves risks to our armed forces and it's being conducted under difficult circumstances. I cannot promise what the final outcome will be," Biden said.
But he said: "we will get you home," adding that the airport was "secured" and that flights could resume.
He said the US would stand by its commitment to evacuate Afghans who had worked with the country and other vulnerable people including journalists and women.
"This is one of the largest and most difficult airlifts in history," Biden added.
The US president said that troops had evacuated 13,000 people from Afghanistan since August 14, in addition to thousands more people evacuated on private charters.
Biden said they were facilitating flights for NATO partners and that the US had provided overwatch for the French convoy evacuating people from the embassy to the airport.
This past week, crowds have gathered in chaotic scenes at the airport waiting to be evacuated, but they have to clear Taliban checkpoints in order to get there.
There were reports that some evacuees had been beaten by the Taliban at airport checkpoints. Pentagon spokesman John Kirby said that 169 Americans were evacuated by US troops from beyond the airport perimeter.
Defence officials in the US said there were 5,800 US troops on the ground in Afghanistan.
Asked by a reporter why the US did not carry out large-scale evacuations earlier in 2021, knowing a Taliban resurgence was on the cards, Biden blamed the Afghan army's failure to hold off the Taliban for longer:
"The overwhelming consensus was that they were not going to collapse... not just abandon, put down their arms, and take off."
But the New York Times recently reported that US intelligence had warned the Afghan military would collapse.
Meanwhile, a recent UN report said the Taliban was intensifying its search for Afghans who worked with US and NATO forces.