7 Marines Killed as Helicopters Collide in Arizona

Seven U.S. Marines were killed when two helicopters collided in Arizona during a training exercise, the military said Thursday.

The accident occurred on a military training range near the city of Yuma on Wednesday evening and the troops who died were from the 3rd Marine Aircraft Wing based at Miramar, in southern California.

"The aircraft, an AH-1W 'Cobra' and an UH-1Y 'Huey', were conducting routine training operations" when they collided around 8:00 pm (0300 GMT Thursday), the U.S. Marine Corps said in a statement.

"The circumstances are being investigated," it added.

MSNBC news reported that there were no survivors in the accident.