Kabul: The US military says four American troops have been killed and two injured in a midair collision of two helicopters in southern Afghanistan.
Hostile fire has been ruled out in the crash, which occurred on Monday morning. No further details were released.
In an unrelated incident, another helicopter went down Monday during a joint, international security force operation against insurgents in western Afghanistan in which a dozen militants were killed.
The US said military casualties were reported and a recovery operation is under way.