U.S. and Japanese forces joined in air-and-sea search missions Saturday for seven American sailors missing after their Navy destroyer and a much-larger container ship collided off the coast of Japan.
The damaged USS Fitzgerald reached its home port at Yokosuka Naval Base, south of Tokyo, after emergency efforts at sea to control flooding.
The operators of the merchant ship, ACX Crystal, reported all of the 20-member Filipino crew were safe.
Civilian and military investigators, meanwhile, began trying to piece together the cause of the nighttime collision.
The Philippine-flagged Crystal is nearly four times as large as the Fitzgerald, an Aegis guided-missile destroyer. Japanese and U.S. vessels and aircraft fanned out across the scene of the collision, about 12 miles off Japan's Izu peninsula. The Japanese coast guard led the search teams.
Three of the Fitzgerald's crew, including the destroyer's commanding officer, Cmdr. Bryce Benson, were evacuated from the damaged vessel and are being treated at the U.S. naval hospital at Yokosuka, the home of the U.S. Navy's Seventh Fleet.
Benson was reported to be in stable condition, while the other two were still having their injuries assessed. The Seventh Fleet had set up an information center for families of sailors serving on the ship.
"Right now we are focused on two things: the safety of the ship and the well-being of the sailors," said Adm. Scott Swift, commander of the U.S. Pacific Fleet.
The USS Dewey, another Navy destroyer and two naval tugboats were at the scene, about 56 nautical miles southwest of Yokosuka. Two Japanese coast guard cutters with helicopters were helping with the search.
The Crystal, which is fully loaded with cargo, is bound for Tokyo, according to a website that tracks maritime traffic. Nippon Yusen K.K., the Japanese shipping company that operates the container ship.
The Fitzgerald, an Arleigh Burke-class destroyer commissioned in 1995, is part of the Yokosuka-based group that includes the aircraft carrier USS Ronald Reagan, but it was operating independently of the carrier when the collision occurred, Flanders said.
The Fitzgerald was operating under its own power after the collision, but was making only about 3 knots (1 to 3 mph). When its crew is at full strength, the Fitzgerald usually has more than 250 personnel aboard and can reach speeds in excess of 30 knots.
It is unclear how the ships collided.
Local broadcaster NHK showed helicopter footage of the container ship with minor damage to its bow, while the Fitzgerald appeared to have significant damage above and below the waterline.
Photos show extensive damage to the Fitzgerald midship on its right, or starboard, side, just below its bridge. It was listing slightly, with water visibly being pumped, as it was towed into harbor.
"Thoughts and prayers with the sailors of USS Fitzgerald and their families," President Donald Trump wrote in a Twitter message Saturday. "Thank you to our Japanese allies for their assistance."
There are extensive international guidelines for accident avoidance at sea known as the International Regulations for Preventing Collisions at Sea, or Colregs. The rules require that ships must have a watch posted at all times and follow a number of collision-avoidance steps when crossing paths with or overtaking other vessels.