As many as five rockets were fired at Kabul's international airport but were intercepted by a missile defense system, as the United States' nears the complete withdrawal of its 

troops from the city. 

The official, speaking on the condition of anonymity, said the rockets were fired early Monday morning Kabul time, though it was unclear if all were brought down by the defense system. 

Initial reports did not indicate any U.S. casualties, but that information could change, the official said. Earlier on Sunday, American forces launched a drone strike in Kabul targeting a suicide bomber in a vehicle who was aiming to attack the airport.