A new video released by the Taliban claimed they were about to take control of Kabul airport, ITV News Rohit Kachroo reports
The last US troops have left Afghanistan, ending America's longest war that has cost of lives of more than 2,400 Americans.
The last US Air Force evacuation flight left Kabul airport late on Monday.
The frantic final exit out of Kabul cost the lives of 13 US service members, some of who were not even born when the war began, in a suicide bombing by Islamic State affiliate, ISIS-K on Thursday.
General Frank McKenzie, head of US Central Command, said the last planes took off from Kabul airport at 3.29pm Washington time, or one minute before midnight in Kabul.
He said some American citizens, likely in “the very low hundreds”, were left behind, but believes they will still be able to leave the country.
The airport, which had become a US-controlled island after the Taliban took over the country, will soon be taken over by the insurgents.
The Taliban celebrated the last US flight departing, firing their guns into the air.
“The last five aircraft have left, it's over!” said Hemad Sherzad, a Taliban fighter stationed at Kabul's international airport.
“I cannot express my happiness in words... Our 20 years of sacrifice worked.”
Secretary of State Antony Blinken said the total number of Americans who are in Afghanistan and still want to leave may be close to 100, and that the US will continue to try to get Americans and Afghans out of the country.
He said: “We have no illusion that any of this will be easy, or rapid.
“We will continue our relentless efforts to help Americans, foreign nationals and Afghans leave Afghanistan if they choose. Our commitment to them holds no deadline.”
He also added that the US Embassy in Afghanistan will remain vacant and that American diplomats will be based in Doha, Qatar.
The final UK flight left on Saturday, bringing an end to the UK's 20-year military involvement in Afghanistan.
More than 15,000 people have been evacuated by the UK since 14 August.
Prime Minister Boris Johnson said now was “a moment to reflect on everything we have sacrificed and everything we have achieved in the last two decades”.
In a video uploaded to Twitter on Sunday morning, Mr Johnson praised the more than 1,000 military personnel, diplomats and officials who took part in the operation in Afghanistan.
Boris Johnson: 'I obviously feel a great sense of regret that we aren’t able to get everybody out in this first phase'
He said: “UK troops and officials have worked around the clock to a remorseless deadline in harrowing conditions.
“They have expended all the patience and care and thought they possess to help people in fear for their lives.
“They’ve seen at first-hand barbaric terrorist attacks on the queues of people they were trying to comfort, as well as on our American friends.
“They didn’t flinch. They kept calm. They got on with the job."
The completion of the US' withdrawal fulfils President Joe Biden's pledge to end what he called a “forever war” that began in response to the attacks of September 11, 2001, that killed nearly 3,000 people in New York, Washington and rural Pennsylvania.
In the last hours in Kabul, American troops faced the daunting task of getting evacuees onto planes while also monitoring repeated threats by the Islamic State group's Afghanistan affiliate, ISIS-K.
A double suicide bombing on Thursday killed 13 American service members and some 169 Afghans.
Speaking shortly after that attack, Biden stuck to his view that ending the war was the right move.
“Ladies and gentlemen,” he said, “It was time to end a 20-year war.”
President Biden believed the war in Afghanistan should have ended 10 years ago after the killing of Osama Bin Laden, whose al-Qaeda extremist group were responsible for 9/11.
Now, the US president faces doubts about his plan to prevent al-Qaida from regenerating in Afghanistan and of suppressing threats posed by other extremist groups such as ISIS-K.