Joe Biden says US 'on pace' to end Afghan mission by August 31

President Joe Biden has informed G7 leaders that the US mission in Kabul is "on pace" to end by an August 31 pullout deadline.

However, Biden has warned the deadline would depend on Taliban cooperation regarding evacuee access to Kabul airport and has ordered contingency plans to "adjust the timeline" if necessary.

Biden sent thousands of US troops to the Kabul airport after the Taliban militant group took over the city and much of the country less than two weeks ago.

The nearly 6,000 US troops are helping to evacuate American citizens and at-risk Afghans and to protect the airport so other countries can evacuate their citizens as well.

Biden sent CIA Director William Burns to meet Taliban leader Abdul Ghani Baradar in Kabul on Monday in the highest level official encounter since the militant group took over the Afghan capital.

The Pentagon earlier said that it was confident the military can evacuate all Americans who want to leave. Whether thousands of at-risk Afghans would all be evacuated was unclear.

"We're absolutely still aiming towards the end of the month," Pentagon spokesman John Kirby said, while adding that the Pentagon may need additional bases to house evacuees from Afghanistan.

Kirby said "several thousand" Americans have been evacuated from Afghanistan but declined to give a more specific figure. He also said he was unable to provide the percentage of Americans in Afghanistan who have now been evacuated.

Afghanistan's new Taliban rulers said on Tuesday they wanted all foreign evacuations from the country completed by August 31 and they would not agree to an extension as Group of Seven leaders met to discuss the crisis.

Western troops have been working frantically to get foreigners and Afghans onto planes and out of the country and Biden has faced growing pressure from allies to negotiate more time for the airlift.

(With inputs from agencies)