A massive search and rescue operation off the Philippine coast is underway for a Marine embarked with the 13th Marine Expeditionary Unit after the amphibious assault ship Essex reported him overboard at 9:40 a.m. local time.

U.S. Navy and Philippine ships and U.S. P-8 Poseidon aircraft have combed roughly 3,000 square nautical miles of the Sulu Sea and the Surigao Strait for the missing Marine. The Essex has also conducted multiple searches inside the ship.

“It’s an all-hands effort to find our missing Marine,” Navy Capt. Gerald Olin, the commander of Amphibious Squadron One and leader of the current search operation, said in a command release. “All of our sailors, Marines, and available assets aboard the USS Essex have been and will continue to be involved in this incredibly important search and rescue operation.”

The Marine was first reported missing while the ship was conducting “routine operations” in the Sulu Sea on Thursday, according to the release.

The search effort also involves aircraft aboard the Essex and the Philippine coast guard.

“As we continue our search operation, we ask that you keep our Marine and the Marine’s family in your thoughts and prayers,” Col. Chandler Nelms, the 13th MEU commander, said in a command release.

The family of the missing Marine has been notified but the Corps is withholding the Marine’s name while search operations are underway.

This story is breaking and will be updated as more information becomes available.