Japanese Naval escort ship JS Kurama has collided with Korean commercial vessel the Carina Star in the Kanmon Strait off southern Japan.
Japanese coastguard spokesman Seishi Izumi said the incident occurred under a bridge linking the Japanese main islands of Kyushu and Honshu about 850km south-west of Tokyo.
The Japanese destroyer is reported to be badly damaged and has caught fire, causing smoke inhalation and bruises to three crew.
A fire on the 7,400t South Korean container vessel Carina Star was extinguished shortly after the collision.
The ignition of a paint locker on the Karuma during the collision caused the majority of the damage to the bow of the ship.
At the time of collision, the JMSDF helicopter defence destroyer DDH-144 Kurama was carrying 360 sailors, following a fleet review at the port of Yokosuka, and was on its way to its home port of Sasebo.