Seven U.S. Navy sailors are dead after the destroyer USS Fitzgerald collided with a merchant vessel off the coast of Japan.

A search for seven missing sailors had been begun after the collision between the Fitzgerald and the Philippine-flagged merchant vessel ACX Crystal, which is about four times the size of the destroyer, happened about 56 nautical miles southwest of Yokosuka at 2:30 a.m. local time. The collision tore into the starboard side of the destroyer’s superstructure above and below the waterline, and sailors spent hours fighting flooding in two berthing compartments, a machinery space and radio room, the Navy said.