The discovery was made upon landing at al Udeid Air Base in Qatar on Monday.
A dramatic video taken earlier Monday showed some people clinging to the plane as it taxied down the runway in Kabul.
A defense official said the individuals swarming the plane had breached the runway from the civilian side of the airport. At the airport in Kabul, there is a side for military operations and another side for commercial flights.
Air operations were suspended for hours at the airport Monday because of the crush of Afghan civilians desperate to leave Kabul. Operations resumed after the U.S. military, Turkish forces and other troops forcibility removed 15,000 Afghan civilians who had breached the runway, a U.S. official said.
VIDEO | Afghans cling to US military plane taking off at Kabul airport
The C-17 had landed on a runway at the airport earlier in the day with a load of cargo, according to the official. After landing, the pilots were surprised when the crew attempted to unload its cargo and it was rushed by hundreds of Afghan civilians. At that point, the aircrew decided it was not safe to unload and began taxiing to fly away to safety
U.S. Pentagon press secretary John Kirby said Tuesday the U.S. will soon have the capacity to evacuate 5,000 to 9,000 individuals a day now on a mix between commercial and military aircraft -- but a lot of that depends on if the Taliban will allow those commercial planes to fly.
The White House said Tuesday that both sides of the airport are open and operational with flights able to land and depart. There were 3,500 U.S. troops on the ground to help control airport operations as of Tuesday morning.
On Monday, more than 700 people were evacuated by the U.S. military, including 165 American citizens, the Pentagon said.
Kirby, at a briefing with reporters Monday, was matter of fact, saying the crush of civilians at the airport came about because "there were a lot of Afghans that wanted to get out of the country."
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