US President Joe Biden has said US troops may remain in Afghanistan beyond its withdrawal period as armed Taliban fighters kept evacuees from reaching Kabul airport.
Mr Biden wants US forces out by the end of this month, but up to 15,000 US citizens are stranded in the country.
The US President told ABC News that the riots in Kabul were inevitable.
Foreign governments are raising the bar for Western citizens and Afghans who have worked with them.
About 4,500 US troops are under temporary control of Karzai International Airport and the nation’s capital, but Taliban fighters and checkpoints are ringing at the perimeter.
The Taliban block the Afghans without travel documents – but also those who fought with valid authorization.
An Afghan interpreter has been shot in the leg by the Taliban as he tries to arrive at the airport on Tuesday evening for an Australian military evacuation flight.
Photos released by SBS showed the man being treated for a gunshot wound by a doctor.
Some US citizens have told the BBC’s US partner CBS News that they are also not capable of embarking on planned evacuation flights.
At a news conference earlier on Wednesday, U.S. Secretary of Defense Lloyd Austin was asked if the U.S. military had the capability to rescue stranded Americans.
“We have the ability not to go out and gather a lot of people,” he replied.
Mr Biden, a Democrat, told the ABC that the United States would remain to get all Americans out of Afghanistan, even though it said it would meet the August 31 deadline for a full withdrawal.
“If there remain American citizens, we will continue to take them all out,” he said.
The U.S. president said between 10,000 and 15,000 Americans would have to be evacuated, along with 50,000 to 65,000 Afghans as former translators for the U.S. military.
Almost 6,000 people have been extracted so far. A Western official told Reuters news agency they were diplomats, security personnel, aid workers and Afghans. The Pentagon told reporters they want to expand the air lift to 9,000 people a day.