Spokesman Maj Adam Wojack says all three attackers were killed, and Afghan and NATO coalition officials are now investigating. The incident took place today in Tagab district in Kapisa province.
The military will not release the contractor's nationality until next of kin has been notified.
An Afghan official in Kapisa province says only that there was a clash between Afghan and US forces that resulted in casualties. He spoke anonymously because the investigation is ongoing.
A Taliban spokesman says they did not carry out the attack. Other smaller insurgent groups are also active in the area.
Kabul: US military officials say three men wearing Afghan army uniforms and driving an Afghan army vehicle forced their way onto a US base in eastern Afghanistan and opened fire, killing one civilian contractor.
First Published: Friday, March 08, 2013, 22:08