US President Joe Biden is set to announce that American troops will leave Afghanistan by 11 September, officials have told US media.
The US would miss a May deadline for a pull-out agreed with the Taliban by the Trump administration last year.
The new deadline would coincide with the 20th anniversary of the terror attacks on the World Trade Center and the Pentagon in the US in 2001.
Mr Biden had previously said the 1 May deadline would be tough to meet.
US and Nato officials have said the Taliban, a hardline Islamist movement, have so far failed to live up to commitments to reduce violence.The Taliban have been warned that if they attack US troops during the pull-out phase, they “will be met with a forceful response”, said a senior administration official who was briefing reporters.
Mr Biden had decided a hasty withdrawal that would put US forces at risk was not a viable option, the official added.
At the same time, a review of US choices determined that now was the time to close the book on the 20-year conflict in Afghanistan to focus on more acute threats.
Mr Biden is due to make the announcement himself on Wednesday.