Helicopter Crash Afghanistan

KABUL, Afghanistan:- Four American troops were killed and two injured when two helicopters collided in southern Afghanistan on Monday.

Hostile fire has been ruled out in the crash, a military statement said. US military spokesman Col. Wayne Shanks said he did not have other details yet about the cause of the collision. Shanks said the injured had been evacuated to hospitals inside Afghanistan. In another incident, another helicopter went down on Monday during an operation by international forces against insurgents in western Afghanistan in which a dozen militants were killed. So far 424 foreign troops have been killed in Afghanistan this year.