- War in Afghanistan (2001-present)
media captionWatch: Top US general admits 'anger and pain' over Afghanistan
The top US general has described the Taliban as a "ruthless group" and says it is unclear whether they will change.
Gen Mark Milley said, however, it was "possible" that the US would co-ordinate with the Islamist militants on future counter-terrorism operations.
US forces withdrew from Afghanistan on Tuesday, ending America's longest war 20 years after launching an invasion to oust the Taliban.
The Islamist are now in control and expected to announce a new government.
Gen Milley was speaking alongside US Defence Secretary Lloyd Austin, in their first public remarks since the last troops left Afghanistan.
US President Joe Biden has been widely criticised over the abrupt manner of the US withdrawal, which led to the unexpected collapse of the Afghan security forces US troops had trained and funded for years.
The Taliban's lightning advance sparked off a frenetic effort to evacuate thousands of foreign nationals and local Afghans who had been working for them.
In the news conference on Wednesday, both Gen Milley and Secretary Austin praised the troops who served in Afghanistan and the massive evacuation mission.
Asked about their co-ordination with the Taliban in getting evacuees to the airport, Gen Austin said: "We were working with the Taliban on a very narrow set of issues, and that was just that – to get as many people out as we possibly could."
Regarding future co-operation, he said: "I would not make any leaps of logic to broader issues."
"In war you do what you must in order to reduce risk to mission and force, not what you necessarily want to do," Gen Milley added.
In total, the evacuation operation saw more than 123,000 people wishing to flee the Taliban regime airlifted out of the country.
The US estimates that there are between 100 and 200 Americans still in Afghanistan.
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US Undersecretary of State Victoria Nuland said "all possible options" were being looked at to get remaining US citizens and people who worked with the US out of the country.
Meanwhile, UK Foreign Secretary Dominic Raab said he was not certain how many UK nationals remained in the country, but that it was believed to be in the "low hundreds".
The Taliban have celebrated the final withdrawal of foreign forces, and are now focusing on forming a government.
The deputy head of the Taliban's political office in Qatar, Sher Abbas Stanekza, told BBC Pashto that a new government could be announced in the next two days.
He said there would be a role for women at lower levels but not in very senior positions.
He also said that those who served in government in the past two decades would not be included.
media captionThe Taliban are asked if there will be a place for women in its new government