YOKOSUKA, Japan >> The search for seven U.S. Navy sailors who went missing after their destroyer collided with a container ship off the Japanese coast was called off after several bodies were found today in the ship’s flooded compartments, including sleeping quarters.

Navy divers found “a number of” bodies in the USS Fitzgerald, a day after the destroyer collided with a Philippine-flagged container ship four times its size, said Vice Adm. Joseph Aucoin, the commander of the Navy’s 7th Fleet. Aucoin, speaking at a news conference at the 7th Fleet’s home base in Yokosuka, Japan, wouldn’t say how many bodies were recovered, pending notification of next of kin.

He said that much of the crew of about 300 was asleep when the collision happened at 2:20 a.m. Saturday, and that one machinery room and two berthing areas for 116 crew members were severely damaged. Aucoin said the destroyer — which returned to Yokosuka on Saturday evening with the help of tug boats — was hit on the side and there was a significant impact.

The victims might have been killed by the impact of the collision or drowned in the flooding, said Navy spokesman Lt. Paul Newell, who led the media on a visit to get a firsthand look at the mangled destroyer.

Aucoin described the damage and flooding as extensive, including a big puncture under the ship’s waterline, and said the crew had to fight to keep the destroyer afloat.

“The damage was significant,” he said. “This was not a small collision.”

“You can’t see most of the damage — the damage is mostly underneath the waterline, and it’s a large gash near the keel of the ship,” Aucoin said. “So the water flow was tremendous, and so there wasn’t a lot of time in those spaces that were open to the sea. And as you can see now, the ship is still listing, so they had to fight the ship to keep it above the surface. It was traumatic.”

The Fitzgerald’s captain, Cmdr. Bryce Benson, was airlifted from the ship’s deck after daybreak Saturday to the U.S. Naval Hospital in Yokosuka with a head injury. Two other crew members suffered cuts and bruises and were also flown out by helicopter.

Aucoin said Benson’s cabin was destroyed. “He is lucky to be alive,” he said.

Aucoin wouldn’t speculate on the cause of the collision, and said he would order a thorough investigation.

Conditions were clear at the time of the collision, though the area is particularly busy with sea traffic.

The damage to the destroyer suggests that the container ship, the ACX Crystal, might have slammed into it at a high speed. This has raised questions as to whether there was proper communication between the two vessels, particularly given how busy the waters where the collision occurred are.

The waters in the area see as many as 400 ships pass through every day, according to Japan’s coast guard. They are especially congested in the early hours of the day, with ships carrying cargo for early morning delivery in Tokyo. The waters also have fast currents, making it a tricky area that requires experience and skill to navigate.

The ACX Crystal weighs 29,060 tons and is 222 meters (730 feet) long, much larger than the 8,315-ton destroyer. The container ship’s left bow was dented and scraped, and it did not appear to have sustained any major structural damage when it was docked in the Tokyo bay late Saturday.

But today, a group of accident investigators from the Japanese transport ministry found damage to the container ship that had been hidden under the waterline when it arrived in Tokyo the previous night. Footage from Japanese broadcaster NHK showed a sharp horizontal cut across the bow area, which looked like a shark’s mouth. Many scratches were also seen in the frontal area.

The container ship was seen making a U-turn before the collision on some ship trackers, a move that has raised questions about what happened. Both Acoin and the Japanese coast guard, however, said it was too early to determine what led to the collision.

The coast guard questioned crew members of the ACX Crystal, and is treating the incident as a case of possible professional negligence, said Masayuki Obara, a regional coast guard official.

All of the ACX Crystal’s 20-member Filipino crew were safe, according to Japanese shipping company Nippon Yusen K.K., which operates the ship.

Japanese Prime Minister Shinzo Abe sent a sympathy message to President Donald Trump today. “We are struck by deep sorrow,” Abe said in the message.

“I express my heartfelt solidarity to America at this difficult time,” he said, praising U.S. servicemen in Japan under the allies’ bilateral security pact.