TOKYO - A Japanese Maritime Self-Defense Force submarine collided Monday with a commercial vessel in the Pacific Ocean off the western main island of Shikoku but no major damage was reported, government officials said.

The 84-meter-long Souryu scraped the hull of the vessel as it was surfacing, the Defense Ministry said, adding three crew members on the submarine were slightly injured.

Top government spokesman Katsunobu Kato said at a press conference that a ship believed to be the commercial vessel, when contacted by the Japan Coast Guard, reported that no impact was felt and it does not appear to have sustained any damage.

The collision occurred at around 10:58 a.m. off Cape Ashizuri in Kochi Prefecture. The ministry said the submarine's antenna mast and other upper parts were slightly damaged but it was able to continue sailing.

Defense Minister Nobuo Kishi said the submarine, which was undergoing routine training, saw the commercial vessel through its periscope as it rose but was unable to avoid it in time. The submarine's communications equipment was damaged in the accident, causing an hours-long delay in reporting the incident by mobile phone, he said.

Kishi told reporters he had been instructed by Prime Minister Yoshihide Suga to confirm the safety of the commercial vessel and provide rescue if necessary, but that the MSDF was unable to confirm the details regarding the ship because it left the scene soon afterward.

The collision, which came on the heels of an MSDF destroyer hitting a Chinese fishing boat in March last year, was "truly regrettable," he said.

The Japan Transport Safety Board said it has launched an investigation into the collision.

The Souryu is a diesel-electric submarine with a standard displacement of 2,950 tons and a crew of about 65. It entered service in 2009 as the first of its class.

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==Kyodo