A Japan Coast Guard ship involved in operations to raise a suspected North Korean spy ship in the East China Sea collided with a Japanese fishing boat Monday morning off the city of Akune, Kagoshima Prefecture, the coast guard said.

The 657-ton Shintatsu Maru collided with the 4.8-ton No. 8 Fukushin Maru at a spot roughly 7.5 km west-southwest of Akune Island at around 6:35 a.m., it said.

The Shintatsu Maru has been involved in the salvage operation since June 27 but left the site and was on its way to shelter in Yashiro Bay in Kumamoto Prefecture because of an approaching typhoon, the coast guard said.

Officials at the coast guard regional headquarters in Kagoshima said a patrol vessel has been dispatched to investigate the collision.

The fishing boat returned to its home port in Higashi, Kagoshima Prefecture, on its own; one of its three crew members was slightly injured.

The coast guard said it would question both parties regarding the incident.

Although the starboard side of the Shintatsu Maru shows a scrape where the two vessels collided, the damage is not major and will probably not affect salvage operations, coast guard officials said.

At the time of the accident, there was little wind and the sea was calm, according to coast guard officials.

The mystery ship lies on the seabed some 90 meters below the surface in China's exclusive economic zone, about 390 km west-northwest of Amami-Oshima Island in Kagoshima Prefecture.

The ship sank after a shootout with Japan Coast Guard vessels in December.

Japan alleges it was a North Korean vessel engaged in spying or drug-running. North Korea has denied having any connection with the ship, but denounced its sinking as "an act of piracy."