The Maritime Self-Defense Force submarine that on Monday collided with a commercial vessel in the Pacific Ocean off Shikoku suffered more extensive damage than initially thought, MSDF officials said Tuesday.

Part of the 84-meter-long Soryu's conning tower has been warped and its starboard hydroplane, which helps control depth, is broken, they said.

The submarine's communications equipment was also damaged in the accident, resulting in the incident not being reported for more than three hours after it occurred at around 10:55 a.m. off Cape Ashizuri in Kochi Prefecture.