Confirmed the death of five Americans marines after their helicopter crashed in a remote area outside San Diego while on a training flight during a severe winter storm, the US Marine Corps announced today.

Their helicopter, a CH-53E Super Stallion;crashed in Pine Valley, a hilly remote area east of the city, last night, Tuesday, while en route to the Marine Corps Air Station in Miramar, California, it said.

The bodies of the crew members were found in a search and rescue operation by Marines and local authorities.

“It is with a heavy heart and deep sorrow that I share [μαζί σας] the loss of five outstanding Marines,” the general said in a statement Michael Borgsulte.

In a statement, the president Joe Biden offered his condolences to the families of the five Marines, saying he and first lady Jill Biden were “overwhelmed by the loss.”

The helicopter had departed from Creech Air Force Base in Nevada, about 60 km northwest of Las Vegas on Tuesday night and flew through rain and snow as it headed west. About eight hours later it was declared overdue.

It is unclear what caused the crash. The Marines said an investigation is underway.