The collision between a Maritime Self-Defense Force destroyer and a South Korean containership Tuesday in the Kammon Strait may have been caused by wrong guidance given by a radar traffic controller minutes before the clash, the Japan Coast Guard said Wednesday.

In the difficult narrow strait separating Kyushu and Honshu, vessels are required to keep to the right as per international navigation rules. But the traffic controller at the JCG's Kammon Strait Maritime Traffic Center in Kitakyushu guided the freighter to the left in order to pass another ship, the JCG said.

According to the Seoul-based operator of the containership, the captain said he had originally planned to pass the right but his ship was guided to the left by the controller.

The destroyer Kurama struck the freighter's starboard bow at around 8 p.m. Tuesday, sparking a fire on the warship's smashed bow and injuring six MSDF sailors.

The crew members of the 5,200-ton Kurama sustained minor burns and light injuries, while no one on the freighter was hurt.

Firefighters from the Moji district of Kitakyushu doused the destroyer's bow with water to contain the blaze early Wednesday.

"The direction from the traffic controller may have been the cause of the accident," a JCG official said.

In an apparent effort to dodge responsibility, however, the JCG said the instructions given to vessels by its traffic control centers aren't binding. They are simply "traffic information" for ships to make their own decisions, it said.

In Tokyo, Defense Minister Toshimi Kitazawa said the destroyer tried to stop before the crash.

"The (MSDF) vessel was in reverse thrust, but it was too late" to avert the collision, the minister said, citing information provided by the Kurama's captain.