The US on Monday (local time) resumed temporarily suspended operations at the airfield after clearing crowds off the runways, said Pentagon.
Violence erupted at the Kabul airport as US forces shot and killed two armed men who fired on them after the Taliban takeover of Afghan capital city Kabul, reported CNN.
The operations resumed while President Joe Biden was addressing the nation about the state of affairs in Afghanistan.
Biden was briefed by his national security team about the situation and then flew from Camp David to Washington to prepare to address the nation as the Taliban solidified their control of the country, reported CNN.
Pentagon spokesman John Kirby told reporters there had been two security incidents at the airfield at Hamid Karzai International Airport "involving armed individuals shooting at US forces."
"In two separate incidents, US forces did respond to hostile threats, and that resulted in the death of two armed individuals," Kirby said during a briefing.
Kirby told reporters that about 2,500 US troops are now at the airport.
The gunfire underscored the turmoil and confusion that have marked the sudden US exit from Afghanistan. All US Embassy staff are at the Kabul airport, which is now under US control as the Pentagon and US allies work to evacuate personnel.
Even as flights began again, the defense official warned that the military anticipates continued sporadic clearing operations if crowds continue to gather, reported CNN.
The US military had temporarily suspended air operations at the airport while US troops cleared Afghans who had flooded onto the airfield in a desperate rush to escape the Taliban, a US defense official told CNN.
Some Afghans had reportedly surged toward departing planes, making frantic attempts to scramble onto and then cling to the aircraft as they took off.
Video has emerged of several people clinging to the fuselage of a US military C-17 aircraft as it taxied Monday. There are scores more people watching or following the plane, some of them underneath its engines. Another video shows a US military Apache helicopter swooping low over the tarmac in what appears to be an effort to disperse the crowds.
A separate video circulated on social media shows a US C-17 soon after takeoff. At least two objects, or people, can be seen falling to the ground as the plane gains altitude.
CNN cannot independently verify that anyone was still clinging to the aircraft when it took off -- and it's not known whether it was the same plane or whether the crew was aware that people were clinging to it at all.
Multiple US defence officials told CNN they could not confirm the incident.