KABUL, Afghanistan » A coalition helicopter crashed in eastern Afghanistan Saturday, but both crew members have been recovered alive, NATO said.

No further details have been disclosed about the crash, which is under investigation.

Aziz Rahman Tawab, acting provincial governor in Kapisa province, said the helicopter crashed into a mountain.

Information about the mission of the helicopter at the time of the crash has not been released.

Aircraft are used extensively in Afghanistan by both NATO and the Afghan government forces to transport and supply troops because the terrain is mountainous and roads are few and primitive.

In September 2010, nine American troops were killed in a helicopter crash in a rugged area of Zabul province in southern Afghanistan. That was the worst helicopter crash for the coalition since May 2006 when a Chinook helicopter went down while attempting a nighttime landing on a small mountaintop in eastern Kunar province, killing 10 U.S. troops.