TOKYO -- A Japanese submarine collided with a civilian cargo ship during exercises in waters off southern Japan Tuesday, defense officials said. There were no immediate reports of any injuries.

The Maritime Self-Defense Forces submarine grazed the civilian vessel during surfacing exercises about 30 miles off the southeastern coast of Miyazaki on Japan's southern island of Kyushu, a defense agency spokesman, speaking on condition of anonymity in accord with agency policy.

No injuries were reported among the 75 crew members of the submarine Asashio. But the spokesman said officials found a dent in the top part of the sub, the apparent result of striking the hull of the ship while surfacing.

The spokesman said the identification and details of the civilian vessel, which was moving northward, were not immediately known.

But he said it was possible that the ship might not have noticed the incident due to the minor impact.

The direction the submarine was heading could not be released, he said.