The beating blades of US military helicopters whisking American diplomats to Kabul's airport has punctuated a frantic rush by thousands of other foreigners and Afghans to flee to safety as well, as a stunningly swift Taliban takeover entered the heart of Afghanistan's capital.
US forces have fired in the air at Kabul's airport on Monday to prevent hundreds of civilians running onto the tarmac, a US official said.
"The crowd was out of control," the official said.
"The firing was only done to defuse the chaos."
Two weeks from the Biden administration's planned full military withdrawal, the United States was pouring thousands of fresh troops back into the country temporarily to safeguard what was gearing up to be a large-scale airlift.
Shortly before dawn on Monday, State Department spokesman Ned Price announced the US had completed the evacuation of its embassy in Afghanistan, lowering the American flag.
At the same time, the administration announced it was taking over air-traffic control at Kabul's international airport, to manage the airlifts out.
Sporadic gunfire there Sunday frightened Afghan families fearful of Taliban rule and desperate for flights out, one of the last avenues for escape in an evacuation made far more urgent by the Taliban's week-long sweep across the country.
NATO allies that had pulled out their forces ahead of the Biden administration's intended August 31 withdrawal deadline were sending troops back in as well this weekend to protect evacuations of their own.
Some complained the US was failing to move fast enough to bring to safety Afghans at risk of reprisal from the Taliban for past work with the Americans and other NATO forces.
Taliban forces moved into the capital early on Sunday and declared they were awaiting a peaceful surrender, capping a stunning sweep of Afghanistan in just the past week.
That arrival of the first waves of Taliban insurgents into Kabul prompted the US to evacuate the embassy building in full, leaving only acting ambassador Ross Wilson and a core of other diplomats operating at the airport.
The US State and Defence departments pledged late Sunday to fly thousands of Americans, local embassy staff and other "particularly vulnerable Afghan nationals" out of the country.
Hundreds or more Afghans crowded in a part of the airport away from many of the evacuating Westerners.
US officials reported gunfire near the airport on Sunday evening and urged civilians to stop coming. US military officials later announced closing the airport to commercial flights, shutting one of the last avenues of escape for ordinary Afghans.
US C-17 transport planes were due to bring thousands of fresh American troops to the airport, then fly out again with evacuating US embassy staffers.
The Pentagon was now sending an additional 1000 troops, bringing the total number to about 6000, a US defence official said.
The Pentagon intends to have enough aircraft to fly out as many as 5000 civilians a day, both Americans and the Afghan translators and others who worked with the US during the war.
Australian Associated Press