TOKYO - The rescue work for the 12 people unaccounted for after a fishing vessel from the Chinese mainland collided with a tanker of China's Hong Kong Special Administrative Region is under way, according to the Chinese Consulate General in Osaka.

Three patrol vessels of the Japan Coast Guard have begun work since early Friday with frogmen sent to search for the missing people, said the consulate general.

The consulate general is keeping close contact with the Japanese side, it said.

The accident occurred on early Thursday in international waters some 400 km north of the Oki Islands in western Japan.

Four of the 16 crew members on board the fishing vessel were rescued, while 12 others were still missing.