SEOUL - A fish-carrying vessel of Cambodian nationality sank off waters in Ulleung Island of South Korea, leaving 12 people missing including nine Chinese sailors, the Yonhap News Agency reported citing the relevant authorities.

The South Korean Coast Guard received a request for rescue around 7:04 amlocal time on Thursday from the Cambodian-flagged, 296-ton boat that carried nine Chinese and three South Korean sailors. At that time, the boat was located 548 km northeast of Ulleung Island of South Korea on the East Sea.

The South Korean coast guard dispatched four ships and four patrol planes to search for the missing sailors, while asking the Japanese and Russian authorities to help with the rescue operation. The Japanese authorities sent two patrol ships and two plans to search for the sailors.

The authorities have yet to identify the cause of the sinking and whether the sailors were alive or dead.