Damaged guided missile destroyer USS Fitzgerald is seen after colliding with a Philippine-flagged container ship on June 17, 2017
Yokosuka (Japan) (AFP) - The US and Japan were conducting a major search operation Saturday to find seven missing American sailors after their navy destroyer collided with a much larger container ship, crushing the side of the military vessel.
Planes, boats and helicopters scoured the seas off Japan's Pacific coast in a bid to find the crew who disappeared in the predawn accident, which also left the USS Fitzgerald's commander injured.
The collision between the 154-metre (500 foot) guided missile destroyer and 222-metre Philippine-flagged container ship ACX Crystal happened around 2:30 am (1730 GMT Friday) off the coast of the Izu peninsula, southwest of Tokyo.
The US warship -- part of its right side caved in as crew members pumped water from flooded areas -- was pulled by a tugboat as it limped back to base in Yokosuka, where the navy said divers were trying to reach parts of the vessel smashed in the accident.
It was not clear where the missing sailors -- still unaccounted for some 20 hours later -- were when the huge vessels collided and the search was expected to continue overnight.
"This has been a difficult day," Vice Admiral Joseph Aucoin, commander of the US 7th Fleet, said in a statement.
"Now that the ship is in Yokosuka, I ask that you help the families by maintaining their privacy as we continue the search for our shipmates."
US President Donald Trump tweeted: "Thoughts and prayers with the sailors of USS Fitzgerald and their families. Thank you to our Japanese allies for their assistance."
The ACX Crystal had large scrapes on its bow, but none of its 20 crew was injured, Japan's coastguard said.
The seven missing US sailors have not been identified.
- 'Going all out' -
"My daughter is on the Fitzgerald," a parent wrote on the 7th Fleet's Facebook page.
"So worried. Just need to hear she is ok. Thinking of all of our sailors and their families!!"
Several other crew members were injured and had to be evacuated by air to hospital, including commanding officer Bryce Benson.
Aerial television footage showed one person lying on a stretcher and a rescuer being pulled up to a helicopter that was hovering above the Fitzgerald.
The accident happened 56 nautical miles (104 kilometres) southwest of Yokosuka, in a busy shipping channel that is a gateway to major container ports in Tokyo and nearby Yokohama.
"The volume of ships is heavy in this area and there have been accidents before," coastguard official Yutaka Saito told Japan's public broadcaster NHK.
NHK said the massive container vessel made a sharp turn around the time of the collision with the smaller US warship, but its captain suggested otherwise.
"(We) were sailing in the same direction as the US destroyer was and then collided," he was quoted as saying by Jiji Press news agency.
Japan's coastguard, which is probing the incident, said it had sent a half dozen vessels, several aircraft and a team of specially-trained rescue personnel to the scene. They were later joined by Japan's Self-Defence Forces.
"We're going all out in the search to find these missing people... but we still haven't found any clues as to where they might be," a coastguard spokesman said.
The US destroyer was commissioned in 1995 and deployed in the Iraq war in 2003.
Television images showed heavy damage to the right side of the ship just ahead of the control tower.
The navy said the crash caused "significant damage" and flooding in two berthing spaces, a machinery space, and the ship's radio room.
"It remains uncertain as to how long it will take to gain access to the spaces in order to methodically continue the search for the missing," the navy said after the ship docked on Saturday evening.
The ACX Crystal -- which sailed to a Tokyo port Saturday -- is a commercial container ship with a Filipino crew, according to its Japanese owner, NYK Line.
It left the central Japanese city of Nagoya on Friday and had been due to arrive in the capital on Saturday.
"We can't comment on the accident as it's being handled by the Japanese coastguard," a company spokesman told AFP.
"We will fully cooperate with authorities investigating the case."