A U.S. Navy destroyer nearly sank after it collided with a merchant vessel off the coast of Japan on Saturday.

"They had to fight this ship to keep it above the surface. It was traumatic," Vice Adm. Joseph P. Aucoin said Sunday, according to the Washington Post.

A majority of the damage to the USS Fitzgerald happened under the waterline near the ship's keel, leading to a "tremendous" amount of water rushing into two berthing cabins and a machinery room, Aucoin said.

The bodies of seven sailors were found in the berthing compartments, the Navy Times reported Saturday.

The investigation into the crash is ongoing.