Four US Marines 'killed in California helicopter crash'

CH-53E Super Stallion goes down near El Centro

A CH-53 Super Stallion approaching the flight deck of the amphibious assault ship USS Bonhomme Richard (EPA)

Four US Marines are presumed dead following a helicopter crash during a training mission in southern California.

The Marine Corps CH-53E Super Stallion helicopter from 3rd Marine Aircraft Wing is understood to have gone down near Plaster City at 2:35pm local time on Tuesday.

“We are currently still responding to what we have confirmed as a single helicopter incident," Naval Air Facility El Centro said in a statement on Facebook.

The identities of the crew members will be withheld until 24 hours after their next-of-kin were told of the tragedy, the military said.

The cause of the crash is being investigated.

It would be the deadliest crash for the Marines since a Navy plane went down in the Mississippi Delta in July, killing all 16 onboard.

Designed to lift heavy objects, such as military vehicles, from ship to shore, it is considered one of the biggest helicopters in the world.