A Marine with the 15 Marine Expeditionary Unit is dead and another eight service members are missing after an amphibious assault vehicle sank on Thursday near San Clemente Island, California, the Marine Corps has announced.

“Search and rescue efforts are ongoing to recover the remaining eight service members,” a I Marine Expeditionary Force news release says. “Assisting in the search efforts are the USS John Finn, three U.S. Navy MH-60 helicopters and multiple small boats from the USS Makin Island, USS Somerset, and USS San Diego, as well as the U.S. Coast Guard Cutter Forrest Rednour and a Coast Guard MH-60 Jayhawk helicopter from Coast Guard Sector San Diego.”

The name of the Marine who died has not been released pending next of kin notification, the news release says.

A total of 15 Marines and one sailor were in the amphibious vehicle at the time, the news release says.

Two Marines were taken to local hospitals, were one is listed in critical condition and the other is stable, the news release says.

The accident happened while the 15 MEU and Makin Island Amphibious Ready Group were conducting training. Marines in the vehicle reported it was taking on water around 5:45 p.m. local time.

“We are deeply saddened by this tragic incident. I ask that you keep our Marines, Sailors, and their families in your prayers as we continue our search,” Col. Christopher Bronzi, 15th MEU commanding officer, said in a statement.

This is a breaking news story. It will be updated as more information becomes available.