A militant attack on a U.S. airbase in Afghanistan early Tuesday damaged the aircraft of the top military officer of the U.S. and injured two maintenance crews, security officials said.

The military chief was not on the premises at the time of the attack.

Two rockets hit the Bagram Air Field outside Kabul overnight causing damage to the C-17 used by General Martin Dempsey, chairman of the U.S. Joint Chiefs of Staff, AFP reported.

NATO spokesman Jamie Graybeal told the Associated Press that the attack did not affect Dempsey's mission in Afghanistan.

Dempsey arrived in Afghanistan Monday for discussions on the progress of the war.