Japan's Coast Guard says a Philippine container ship reported a collision with a US navy vessel about 20 kilometers off Shizuoka Prefecture around 2:30 AM Saturday, Japan Time.
Coast Guard and US navy officials say the Philippine container is believed to be the ACX Crystal, which is 222.6 meters long and weighs 29,060 tons.
The navy vessel is said to be the USS Fitzgerald, a 154-meter long Aegis destroyer weighing 8,315 tons.
Helicopter footage from NHK shows considerable damage to the right side of the Aegis destroyer.
An orange hose is visible on the deck, and many crew members can be seen checking the damage.
A Coast Guard vessel has arrived near the destroyer.
It's unknown whether anyone has been injured.
The Coast Guard has dispatched patrol vessels and one helicopter.