Two helicopters with the NATO-led International Security Assistance Force (ISAF) collided in the air Monday morning, leaving four soldiers dead and two others injured in southern Afghanistan, said a statement of the alliance, Xinhua reported.
"Two ISAF helicopters were involved in what was believed to be mid-air collision in southern Afghanistan this morning. Four ISAF service members were killed and two others injured in the incident," the statement said.
It noted that the incident is under investigation, but "it is confirmed that hostile fire was not involved."
Meantime, U.S. spokesman Colonel Wayne Shanks, confirms the four ISAF service members were from the U.S.
Conflicts and violence have claimed at least 424 international troops, with 256 Americans, so far this year in war-torn Afghanistan.