Five Marines flying from Nevada to California died in a helicopter crash, US military officials confirmed.
A search-and-rescue operation was launched for the CH-53E Super Stallion after it was “reported overdue” on Wednesday.
The helicopter was on a training flight from a Nevada Air Force base to an air station near San Diego.
Officials said its last reported location was received on Tuesday evening at about 23:30 local time.
The helicopter was later found on Wednesday morning in the snow-covered California mountains – about 45 miles (74km) from its destination.
“It is with a heavy heart and profound sadness that I share the loss of five outstanding Marines from 3d Marine Aircraft Wing and the ‘Flying Tigers,'” Maj Gen Michael J Borgschulte, commander of the 3rd Marine Aircraft Wing, said in a statement on Thursday.
As the Marines’ families are being notified, their names were not immediately released.
US president Joe Biden offered his condolences to the families of the troops after the news broke on Thursday morning.
“Our service members represent the very best of our nation – and these five Marines were no exception,” Mr Biden said in a statement.
Efforts are now underway to recover the troops’ bodies, Maj Gen Borgschulte said. The Marines have also launched an investigation into the crash.
Secretary of Defense Lloyd Austin acknowledged the ongoing investigation in a statement on Thursday afternoon.
He added that the incident served as a reminder of service members’ sacrifice and said his “prayers are with these brave Marines and their families, loved ones, and teammates”.
The five service members were assigned to Marine Heavy Helicopter Squadron 361, part of the 3rd Marine Aircraft Wing.
They had departed for Marine Corps Air Station Miramar in San Diego late on Tuesday following a training at Creech Air Force Base near Las Vegas.
The Marine Corps said that the helicopter was reported overdue at 01:00 local time (08:00 GMT) on Wednesday. Fire crews were then alerted to the missing aircraft shortly thereafter at 02:20 local time.
The crews were dispatched to an area near Lake Morena, California. They were able to locate the aircraft hours later near Pine Valley, California, in the Cuyamaca Mountains.
Rescuers were “using ground and aviation assets to locate the aircrew in co-ordination with the San Diego County Sheriff’s Department and multiple federal, state and local agencies”, the 3rd Marine Aircraft Wing had said in a statement.
The search efforts were hindered by heavy snow and wintry conditions in the area, officials said.
The incident comes in the wake of a powerful winter storm in the region that dumped heavy rain and several inches of snow in mountainous areas.
The CH-53E Super Stallion is among the largest helicopters used by the military. Over the past three decades, it has often been brought in for heavy-lifting operations.
But it has a chequered safety record, and there have been several serious accidents involving the helicopter in recent years.
In April 2018, four troops were killed when their Super Stallion crashed near El Centro, California, while on a training mission.
In a separate incident in January 2016, 12 Marines were killed when two Super Stallions collided over the Pacific near Oahu in Hawaii.
By BBC News
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