A U.S. Marine Corps helicopter crashed near El Centro, Calif., on Tuesday afternoon during a routine training mission, and the military says all four aboard are presumed dead.

"Four crew members were aboard" the CH-53E Super Stallion helicopter, the 3rd Marine Aircraft Wing said in a statement . "The status of all four is presumed dead pending positive identification."

The helicopter went down about 2:35 p.m. local time, the statement said. El Centro is about 100 miles east of San Diego.

The cause of the crash is being investigated, the statement said.

Earlier, Reach Air Medical quickly dispatched two helicopters to the crash site, a spokesperson, Donnie Wharton, told The Desert Review.

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