7 Marines killed after helicopters collide near Arizona-California border

Seven Marines died when their helicopters collided in midair Wednesday night around the Arizona-California border, defense officials told NBC News. There were no survivors.

The Marines, from the 3rd Marine Aircraft Wing based in Miramar in Southern California, were conducting a routine training exercise at about 8 p.m. local time when their AH-1W "Cobra" and UH-1Y "Huey" helicopters collided.

The cause of the crash, which occurred in a remote part of the Yuma Training Range Complex, is under investigation, the Marines said in a statement.

Two Marines were on one of the helicopters, while five were on the other, Marine Capt. Staci Reidinger told KYMA-TV.

The identities of the Marines killed have not been released pending formal notification of next of kin.

The incident comes after a number of training fatalities in recent years. Last September, two Marines died when their AH-1W Super Cobra helicopter went down in Camp Pendleton, according to the Marine Corps Times. And in July, a Marine sergeant was killed in the crash of a UH-1Y Huey helicopter, also at Camp Pendleton, while five others onboard were injured, the Marine Corps Times reported.