He said "a significant portion of the crew was sleeping" when the destroyer collided with a Philippine-flagged container ship, the ACX Crystal.
"Families of the deceased are now being alerted and provided the help they need during this challenging time", the 7th Fleet stated.
Seven sailors who had been missing were found dead in flooded living compartments Sunday morning, Japan time, the Navy's 7th Fleet said.
With the aid of tugboats, the badly damaged guided-missile destroyer Fitzgerald returned to its home port Yokosuka Naval Base, south of Tokyo, about 16 hours after the collision.
The collision between the 10,000-ton USS Fitzgerald and the 29,000-ton merchant vessel ACX Crystal occurred early Saturday local time almost 60 miles from the coast of Japan. Bryce Benson. The sailors are under observation at the U.S. Naval Hospital Yokosuka and have been in stable condition.
The U.S. 7th Fleet said in a statement that the crash damaged two berthing spaces, a machinery room and the radio room.
Naval commanders praised the sailors for containing flooding caused by the collision, stabilizing the ship and sailing it back to port at the USA naval base in Yokosuka.
"There was a big puncture, a big gash underneath the waterline" along the bottom of the ship, Aucoin said.
The Japanese coast guard said it received an emergency call from the container ship, the ACX Crystal, reporting the collision around 2:20 a.m. local time. The other two sailors suffered lacerations and bruises.
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He thanked "our Japanese allies" for their swift assistance, and said the Navy will full investigate the cause.
Those who did not survive might have killed by the impact of the crash or drowned by the flooding, said Navy spokesman Lt. Paul Newell, who led reporters for a first look at the mangled vessel.
(AP Photo/Eugene Hoshiko). People watch the damaged USS Fitzgerald being towed near the U.S. Naval base in Yokosuka, southwest of Tokyo, after the U.S. destroyer collided with the Philippine-registered container ship ACX Crystal in the waters.
At around 29,000 tons displacement, the ship dwarfs the 8,315-ton U.S. warship.
The cause of the accident is under investigation.
Despite the significant damage to the destroyer, Aucoin said he expected it would rejoin the fleet.
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.
The initial Navy investigation will gather facts about what happened, with the 7th Fleet commander eventually deciding what disciplinary action is warranted, the official said.
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