TOKYO (XINHUA) - Three Indonesian crew members are unaccounted for after two South Korean fishing boats collided off Japan's Hokkaido on Thursday (July 26), said the Japan Coast Guard.

One of the two fishing boats sank after the collision, and 35 of its 38 crew members were rescued by nearby fishing vessels, while three others remain missing.

All of the three missing crew members were Indonesian, while the other crew members were either South Korean or Indonesian, according to local reports.

The Japan Coast Guard said it received a distress signal from the South Korean fishing boat "101 Kumyang" around 6am local time in the morning.

The signal was sent from waters some 460km south-east of Cape Nosappu, the easternmost point of Hokkaido.

The Japan Coast Guard has sent aircraft and patrol boats to search for the missing crew members, but heavy fog and high waves around the site could hinder the search and rescue operation.