President Joe Biden told the Taliban on Tuesday that U.S. would stick to its promise to lead Kabul by Aug. 31 if it stuck to its agreement to allow Westerners and vulnerable Afghans free passage to the airport.
The U.S. has ramped up its airlift in recent days amid fresh reports of human rights abuses that will fuel fears for the fate of people who worked with American troops.
Adding to the sense of urgency, the country's new Taliban rulers said that all evacuations must be completed by the end of the month and announced a ban on Afghans traveling to the airport.
Biden said the U.S. was 'on pace' to complete its mission by Aug. 31 but said he had asked officials to draw up contingency plans if U.S. troops had to stay longer.
'Each day of operations brings added risk to our troops, but the completion by the 31st depends upon the Taliban continuing to cooperate, allow access to the airport for those who are transporting out and no disruptions to our operations.
'In addition, I've asked the Pentagon and the State Department for contingency plans to adjust the timetable, should that become necessary.
'I'm determined to ensure that we complete our mission.'
Witnesses said the Taliban blocked roads to the airport and fired in the air to disperse crowds. And Politico reported that American citizens were turned away from the airport.
The Biden administration is under intense pressure to wrap up a chaotic evacuation without leaving Americans or Afghans with visas behind.
He was due to deliver an update at midday but - in a sign of a White House trying to keep abreast of a fast moving scene in Kabul - he did not begin his remarks until after 5pm.
He began with the good news, welcoming a vote in the House to pass his huge $3.5 trillion spending plan.
But after offering an update on progress in Kabul he walked out the Roosevelt Room without responding to journalists' shouted questions.
Biden said U.S. troops were 'on pace' to leave by August 31 so long as the Taliban kept its word to allow Afghans and Westerners to reach Kabul airport
President Joe Biden will stick to his August 31 deadline to withdraw U.S. troops from Afghanistan despite pressures from G7 leaders to extend it
White House Press Secretary Jen Psak
Earlier he spoke with leaders of the G7 major industrialized nations - Britain, Canada, France, Germany, Italy, and Japan - telling them that completing the operation depended on continued cooperation with the Taliban.
But at the same time it emerged that U.S. had already begun drawing down troops at the airport.
A diplomatic source in Washington said allies had been warned to expect that U.S. forces would begin their 'retrograde' from Hamid Karzai Airport on Tuesday in order to be out by the end of the month.
White House Press Secretary Jen Psaki said U.S. officials believed Americans and Afghan allies were still able to reach the airport.
'I think that's safe to say what I'm talking about is the individuals we have prioritised, those who have fought alongside us, who are eligible for some special immigrant visas, otherwise wise we are facilitating their departure and that our expectation is that they will be able to reach the airport,' she said.
The Aug. 31 departure gives the Biden administration just seven days to evacuate thousands of American citizens and local allies still stranded on the ground.
The US ramped up the airlift by evacuating 21,600 people in the past 24 hours, but they still don't know the exact number that need to be rescued - and now time is rapidly running out.
British Prime Minister Boris Johnson, French President Emmanuel Macron and German Chancellor Angela Merkel were among the leaders who urged Biden to keep boots on the ground longer during the Tuesday meeting. European leaders are worried there is not enough time to evacuate everyone who wants out.
Biden spoke for seven minutes during the virtual meeting, according to officials.
He had been scheduled to deliver an update on progress at midday, but the time came and went without word from the White house.
It all suggested a frantic atmosphere behind the scenes as aides and advisers juggled logistics and coordinated with the Pentagon and State Department after Taliban spokesperson Zabihullah Mujahid refused to extend the troop deadline despite secret talks with CIA Director Bill Burns.
'They are capable of evacuating their citizens and troops by August 31', the defiant Taliban spokesman said. 'All people should be removed prior to that date. After that we do not allow them. We will take a different stance.
Biden met with G7 leaders on Tuesday morning to discuss Afghanistan
An aerial picture taken Monday shows crowds and traffic outside the Kabul airport as Americans and Afghan allies attempt to flee Afghanistan
Satellite images from Monday show a massive crowd around a gate near a military checkpoint outside the Kabul airport
The Pentagon recommendation was made on Monday based on concerns about security risks to American forces, a senior administration official said. Biden had asked the Pentagon for contingency plans to stay longer should it be necessary, the official noted.
American officials told the Taliban that the U.S. withdrawal by Biden's Aug. 31 deadline is contingent on the group's cooperation in facilitating evacuations, the official said.
Former President Trump kept up his critical commentary claiming,