Seven US Navy sailors are missing off the coast of Japan after an Aegis guided missile destroyer, the USS Fitzgerald, collided with a container ship early on Saturday, causing significant damage and flooding.
Three sailors, including the destroyer's commanding officer, Commander Bryce Benson, were evacuated from the damaged vessel and are being treated at the US naval hospital at Yokosuka, the home of the US Navy's Seventh Fleet.
Commander Benson was reported to be in stable condition in the hospital, while the other two were still having their injuries assessed. The Seventh Fleet had set up an information centre for families of sailors serving on the ship.
The cause of the collision was not yet clear.
"Right now we are focused on two things: the safety of the ship and the well-being of the sailors", said Admiral Scott Swift, commander of the US Pacific Fleet.
The USS Dewey, another destroyer, and two naval tugboats were at the scene, about 19 kilometres from the Izu Peninsula and 103 kilometres southwest of Yokosuka, searching for the missing sailors on Saturday. Two Japanese coast guard cutters with helicopters were helping.
The Fitzgerald collided with a fully laden, Philippine-flagged container ship, the ACX Crystal, early on Saturday morning.
The Crystal is about 220 metres long and was bound for Tokyo, according to a website that tracks maritime traffic.
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. Water was being pumped from aboard the navy ship.
The Fitzgerald 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, a spokesperson said.
The Fitzgerald was operating under its own power after the collision.
When its crew is at full strength, the Fitzgerald usually has more than 250 personnel aboard and can reach speeds well over 40 kilometres per hour. It is unclear how fast the destroyer was travelling when it and the merchant ship collided.
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.
While such incidents are rare, this is the second time this year that a US Navy ship has collided with another shipping vessel.
In May, the US Navy's USS Lake Champlain collided with a South Korean fishing vessel but both ships were able to operate under their own power.
The Washington Post