US President Joe Biden is set to announce that American troops will leave Afghanistan by the 11th of September.
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.
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.