The five Marines who went missing while traveling aboard a helicopter from Nevada to California have been found dead, officials said Thursday morning. 

Officials said Thursday that the Marines were conducting a training exercise and flying a CH-53E Super Stallion helicopter from Creech Air Force Base in Clark County, Nevada to Marine Corps Air Station Miramar in San Diego, California. The helicopter reported its last-known location at around 11:30 p.m. on Tuesday, and was reported overdue at around 1 a.m. Wednesday morning, according to the Marine Corps. 

The crashed helicopter was found in a mountainous, rugged area east of San Diego at around 9 a.m. on Wednesday, officials said. Search and rescue crews and federal and local agencies looked for the Marines as rain and snow lashed the area. The weather conditions complicated the search efforts, with the San Diego County Sheriff's Department saying that heavy cloud cover early Wednesday morning prevented it from deploying its helicopter. The U.S. Forest Service and the U.S. Border Patrol also contributed to the search effort, since the area where the helicopter crashed is near the U.S.-Mexico border. 

The five Marines were assigned to Marine Heavy Helicopter Squadron 361, Marine Aircraft Group 16, 3rd Marine Aircraft Wing, the Marine Corps said. Their identities have not been shared as part of a standard military procedure to not identify deceased service members until 24 hours after all next-of-kin notifications have been made. 

"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" while conducting a training flight last night," said Maj. Gen. Michael J. Borgschulte, commanding general of 3rd Marine Aircraft Wing, in a statement provided to CBS News. "These pilots and crewmembers were serving a calling greater than self and were proud to do so. We will forever be grateful for their call to duty and selfless service. To the families of our fallen Marines, we send our deepest condolences and commit to ensuring your support and care during this incredibly difficult time."

President Joe Biden addressed the crash in a statement on Thursday morning, saying that he and first lady Jill Biden are "heartbroken" at the loss of the Marines. 

"As the Department of Defense continues to assess what occurred, we extend our deepest condolences to their families, their squadron, and the U.S. Marine Corps as we grieve the loss of five of our nation's finest warriors," Mr. Biden said, in part. "Our service members represent the very best of our nation—and these five Marines were no exception. Today, as we mourn this profound loss, we honor their selfless service and ultimate sacrifice—and reaffirm the sacred obligation we bear to all those who wear the uniform and their families." 

Officials said that efforts to recover the bodies of the Marines and the equipment from the helicopter are underway. An investigation into the crash is also ongoing.  

This is a developing story. Check back for updates. 

In:
• U.S. Marine Corps
• California
• Military Helicopter

Kerry Breen

Kerry Breen is a reporter and news editor at CBSNews.com. A graduate of New York University's Arthur L. Carter School of Journalism, she previously worked at NBC News' TODAY Digital. She covers current events, breaking news and issues including substance use.

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