US secretary of state Antony Blinken said the administration believes about 1,500 American citizens remain in Afghanistan 12 days into a massive US military airlift.

Mr Blinken said at a news conference that another 4,500 Americans have been evacuated in a US-run, round-the-clock operation since the Taliban reached the capital on August 14, completing a sudden rout of the US-backed Afghan government and military.

Mr Blinken’s count comes after days of pressing for official estimates of how many Americans remain to be safely got out of the country, ahead of a planned US troop withdrawal.

American officials are in contact with about 500 American citizens to try to get them safely out of the country, the US official said.

Mr Blinken described ongoing efforts to reach the final 1,000 Americans, ahead of the US withdrawal.

“We’re aggressively reaching out to them multiple times a day, through multiple channels of communication, phone, email, text-messaging, to determine whether they still want to leave,” he said.