Human Interest Marine Dead, 8 Missing After 'Tragic' Training Accident in California: 'We Are Deeply Saddened' Search and rescue efforts were still underway as of Friday morning By Joelle Goldstein Joelle Goldstein Twitter Joelle Goldstein is a TV Staff Editor for PEOPLE Digital. She has been with the brand for five years, beginning her time as a digital news writer, where she covered everything from entertainment news to crime stories and royal tours. Since then, she has worked as a writer-reporter on the Human Interest team and an associate editor on the TV team. In her current role, Joelle oversees all things TV and enjoys being able to say she has to watch The Kardashians, Dancing with the Stars and America's Got Talent for "work". Prior to joining PEOPLE, Joelle was employed at The Hollywood Reporter. She graduated from Ithaca College with a degree in Television-Radio (and an appearance in the NCAA Women's Volleyball Final Four!) People Editorial Guidelines Published on July 31, 2020 11:08 AM Share Tweet Pin Email San Clemente Island. Photo: Lenny Ignelzi/AP/Shutterstock One U.S. Marine has been confirmed dead while eight others remain missing following a training accident off the coast of Southern California, the U.S. Marine Corps 1st Expeditionary Force announced in a media release. The fatal incident occurred on Thursday during a 15th Marine Expeditionary Unit (MEU) and Makin Island Amphibious Ready Group routine training exercise near San Clemente Island, officials said. Fifteen Marines and one sailor were inside the amphibious assault vehicle (AAV) when they reported taking on water at about 5:45 p.m. local time, according to officials. Following the "mishap," one Marine who served on the 15th MEU, I Marine Expeditionary Force, was pronounced dead at Scripps Memorial Hospital La Jolla, according to the press release. Their identity will be withheld until 24 hours after next of kin have been notified. Marine, 21, Killed During Training Exercise in California Two others suffered injuries and were transported to local hospitals, where one was listed in critical condition and the other in stable condition, officials said. A total of eight people were recovered from the AAV, while another eight remain missing in the waters. Search and rescue efforts are currently underway by the Marines with help from the U.S. Navy and Coast Guard, according to the press release. "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. RELATED VIDEO: 11 Servicemen Presumed Dead After Army Helicopter Crash According to the United States Naval Institution, the AAV has been the "primary infantry sea-to-land transport vehicle since the 1970s," and the Marines are currently testing its replacement. The incident remains under investigation, officials said.