Speaking forcefully, US president Joe Biden defended his decision to end the war in Afghanistan, saying America needed to focus on developing threats and calling on US policymakers to “learn from our mistakes” in a grueling conflict that killed about 2,400 US troops, cost trillions of dollars and resulted in a Taliban victory.

Mr. Biden sought to strike back at those who have criticized his administration’s handling of the final chapter of America’s longest war, calling the airlift operation from Hamid Karzai International Airport that rescued more than 120,000 people an “extraordinary success”.

The final US plane left Afghanistan on Monday and Taliban fighters entered Kabul’s airport immediately after, firing tracer rounds into the night skies in celebration.

Mr Biden said that a Taliban takeover would always have resulted in a rush of thousands of Afghans to the airport and he said he did not regret ending the evacuation mission.

“I was not going to extend this forever war and I was not extending a forever exit,” Mr Biden said in a televised address from the White House.

“It was time to end this war,” he later added as he pounded his fist on the lectern.

Thousands of Afghans who had worked with US forces over the years as well about 200 Americans, most dual citizens, are still in Afghanistan. It is not clear how many are choosing to stay or were unable to reach the airport by the evacuation deadline.

“For those remaining Americans, there is no deadline. We remain committed to get them out if they want to come out,” he said.

Mr Biden said in a statement that he asked Secretary of State Anthony Blinke to co-ordinate with international partners to hold the Taliban to their promise of safe passage for Americans and others who want to leave in the days ahead.

The US will also maintain a diplomatic presence in Doha to help those who choose to leave at a later date — Americans or any other foreign national.

“This will include work to build on the UN Securrity Council Resolution passed just yesterday that sent the clear message of what the international community expects the Taliban to deliver on moving forward, notably freedom of travel,” Mr Biden continued.

Mr Biden’s 30-minute speech was in turns angry, exasperated and resolute. He did not acknowledge the suffering that millions of Afghans have endured over the two decades since the US-led invasion and his message was squarely aimed at American viewers.

“I refuse to open another decade of warfare in Afghanistan. We’ve been a nation too long at war. If you’re 20 years old today, you’ve never known an America at peace,” he said.

As he has done previously, Mr Biden took responsibility for the events of recent weeks but again pointed to the retreat deal the Donald Trump administration brokered with the Taliban last year.

“By the time I came to office, the Taliban was in its strongest military position since 2001, controlling or contesting nearly half of the country,” he said.

“We were left with a simple decision. Follow through on the commitment made by the last administration and leave Afghanistan, or say we weren’t leaving and commit … tens of thousands more troops going back to war. That was the choice, the real choice.”

Mr Biden also lashed out at exiled Afghan President Ashraf Ghani, who fled his country on August 15 as the Taliban rolled into Kabul.