Arizona: Helicopter crash kills 7 US Marines

US defense officials today said seven Marines were killed in a Wednesday helicopter collision near Yuma, Arizona, CNN reported.

Officials said the reason for the crash, in which two helicopters collided during a training course, is under investigation. The soldiers were a part of the 3rd Marine aircraft wing.

The names of the seven killed will not been released until their relatives have been notified, according to the official Marines statement published by USA Today.

The statement said the collision of helicopters AH-1W "Cobra" and a UH-1Y "Huey" took place "around 8 p.m." in a "remote portion of the Yuma Training Range Complex."

The 10,000-mile military training site lies along the southern California-Arizona border and includes a Chocolate Mountain Aerial Bombing area used for training purposes, according to GlobalSecurity.