UPDATE: The Marine Corps Air Station-Miramar now says one of the Marines killed was based out of Yuma.
A collision of two helicopters during training exercises last night along the Arizona/California border killed seven Marines, according to a Marine Corps spokeswoman.
Lieutenant Maureen Dooley tells New Times that as of now, the Marine Corps believes the seven Marines were stationed at Camp Pendleton in southern California.
The names of the Marines killed will not be released until at least tomorrow.
According to Major Carl Redding -- who's posting updates about the collision online -- the Marines were part of the "Huey and Cobra squadrons," a reference to the types of helicopters involved.
Redding confirms both of those squadrons are based out of Camp Pendleton, but the helicopter operations are headquartered out of California's Miramar Air Base as part of the 3rd Marine Aircraft Wing.
Redding cites the specific location of the crash as being on federal land, 3 kilometers west of the Yuma Training Range.
Senator John McCain, a Navy veteran, has already issued a statement about the collision.
"My thoughts and prayers are with the families of the seven Marines killed in the helicopter collision last night near Yuma, Arizona," McCain says. :This tragedy is a grave reminder of the sacrifices the men and women of our armed forces make to keep us safe -- both in training here at home and in combat abroad."
Check back for updates.