SAN DIEGO (AP) — Multiple agencies continued to search Sunday for a U.S. Marine who went missing during a training exercise off the coast of southern California, military officials said.

Crews began searching for the Marine early Thursday morning, shortly after midnight, according to a Navy news release. The Marine was reported missing from the USS Anchorage during integrated training between the Makin Island Amphibious Ready Group and the 13th Marine Expeditionary Unit.

It’s at least the second time in six weeks that the U.S. military has been forced to look for missing members. The remains of the second of two U.S. Army soldiers who went missing during military exercises in Morocco were recovered in May, the Army said, ending a multinational search operation that deployed air, naval and artificial intelligence assets.

“Our thoughts and prayers are with the family and all who are affected during this difficult time,” the Navy said in the news release this week about the missing Marine.

The Navy transitioned from search-and-rescue efforts to a search-and-recovery operation Friday evening. The Marine’s name was being withheld pending the notification of family.

The search has covered about 2,400 square miles (6,200 square kilometers) and involved three surface ships and 12 aircraft from the Navy, Marine Corps, Coast Guard and Air Force, officials said.

The USS Anchorage is an amphibious transport dock ship based at Naval Base San Diego.