Insurgents shot down a U.S. helicopter after exchanging fire with its crew in central Afghanistan on Monday, while a suicide bomber in the north killed two American soldiers inside a police station, officials said.

The crew of the helicopter, forced down in a province neighboring Kabul, were rescued and troops were "in the process of recovering" the aircraft," said Lt. Cmdr. Walter Matthews, a U.S. military spokesman.

"The helicopter crew exchanged fire with the enemy before the damage brought the helicopter down," Matthews said.