Five US marines killed in helicopter crash as Biden 'heartbroken'
Five US marines have been killed in a helicopter crash in California.
The aircraft, a CH-53E Super Stallion, went down on Tuesday night during stormy weather in mountains outside San Diego.
The helicopter was discovered on Wednesday morning near the mountain community of Pine Valley, about 45 miles from the city, said the military.
President Joe Biden said in a statement that he and First Lady Jill Biden were "heartbroken" to learn of the marines' deaths.
"Our service members represent the very best of our nation - and these five marines were no exception," Mr Biden said.
The marines who were killed were not immediately named but they were assigned to the Marine Heavy Helicopter Squadron 361, Marine Aircraft Group 16, 3rd Marine Aircraft Wing, the military said.
Major General Michael J Borgschulte, commander of 3rd Marine Aircraft Wing, said in a statement: "It is with a heavy heart and profound sadness that I share the loss of five outstanding marines from 3rd Marine Aircraft Wing and the Flying Tigers."
The helicopter had been returning to the Marine Corps Air Station Miramar in San Diego after training at Creech Air Force Base, northwest of Las Vegas.
A search and rescue effort got under way as a turbulent storm dumped heavy snow and record rain over California.
The operation involved federal, state and local agencies, including the US Forest Service, US Border Patrol, San Diego County Sheriff's Department and the state Civil Air Patrol.
The Super Stallion helicopter - the US military's largest - can carry dozens of people and requires four crew members - a pilot, co-pilot, crew chief, and mechanic.
More than 130 are in operation in the US military, with the aircraft performing "a full range of military combat operations in Beirut, Somalia, the Persian Gulf, Afghanistan, Iraq and Libya", according to a US Navy website.
The Super Stallion helicopter has been involved in several other deadly accidents.
Four US marines were killed in 2018 when their aircraft crashed near the California-Mexico border during a training mission.
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The Marine Corps ruled out pilot error for the accident. The victims' families later sued two companies they alleged provided a defective part that they blamed for the crash.
In 2005, a Super Stallion went down in a sandstorm in Iraq, killing 31 people on board. The accident, blamed on pilot error, was the single deadliest loss of US troops during the war.