One U.S. Marine is dead and eight are missing off the Southern California coast after an unspecified training “mishap” involving an amphibious assault vessel. The Marine Expeditionary Force confirmed in a tweet early Friday: “One Marine has died, eight service members remain missing and two were injured after an AAV mishap July 30 off the coast of Southern California.” All of the troops are assigned to the 15th Marine Expeditionary Unit. The MEF said that search and rescue operations are still ongoing. It provided no further details. Col. Christopher Bronzi, 15th MEU Commanding Officer, said in a statement posted to Twitter: “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.”