Joe Biden will decide whether or not to extend the Afghanistan evacuation deadline within the next 24 hours.
With thousands of desperate Afghans and foreigners massed at Kabul's airport in the hope of fleeing the Taliban, the US President is expected to decide as early as Tuesday on extending the August 31 deadline.
On Monday, an administration official said that Biden will make the crucial decision on extending the timeline to give the Pentagon time to prepare.
Department of Defence officials said it would still take days to fly out the 6,000 troops deployed to secure and run the airlift.
Some advisers were arguing against extending the self-imposed deadline for security reasons.
Biden could signal his intentions at a virtual meeting of the G7 which will be held on Tuesday.
Two US officials had said the expectation was that the US would continue evacuations into September.
A senior State Department official told reporters the country's commitment to at-risk Afghans "doesn't end on August 31."
But a Taliban official said foreign forces had not sought an extension and it would not be granted if they had.
Taliban spokesman Suhail Shaheen told Sky News: "This is something ... you can say it's a red line.
"President Biden announced this agreement that on August 31 they would withdraw all their military forces. So, if they extend it that means they are extending occupation while there is no need for that.
"It will create mistrust between us. If they are intent on continuing the occupation, so it will provoke a reaction."
Downing Street said the UK will continue its evacuation process "as long as the security situation allows" when asked about the Taliban spokesman's remarks.
The Prime Minister's official spokesman that "discussions on the ground" have been held with the Taliban and added: "I've seen the reports. I don't think we've had any direct communication to that end."
Meanwhile, it was reported that a firefight at one of the gates of Kabul's international airport killed at least one Afghan soldier on Monday.
The Foreign Office said it had sent five extra staff to the airport, taking its total working on the evacuation effort in the capital to 19.
Shadow foreign secretary Lisa Nandy said Mr Johnson must use the G7 call to "step up and demand" the extension past August 31, secure a pact to "deal with the unfolding refugee crisis" and develop a strategy to support those left behind.
The chaos at the airport has also disrupted aid shipments.
The World Health Organization said tons of medical supplies were stuck because Kabul airport was closed to commercial flights.
Leaders of the Taliban, who have sought to show a more moderate face since capturing Kabul, have begun talks on forming a government, while their forces focus on the last pockets of opposition.
