TOKYO (Reuters) - Russian authorities have seized a Japanese cod fishing boat and taken it to a Russian-controlled island claimed by Japan, media reports and a fishermen’s association said on Wednesday.

Six fishermen were on the boat but further details were not known, an official at Habomai fishermen’s cooperative association in Japan’s northern region of Hokkaido, said.

The boat was inspected by Russian border guards and was taken to a port at Kunashiri island, Kyodo news agency and public broadcaster NHK reported.

There was no immediate comment from Russian authorities.

Kunashiri island is one of the four Russian-held islands off Hokkaido, which Japan calls the Northern Territories, known as the Southern Kuriles in Russia.

The seizure of the Japanese vessel came after Russia last month released five Japanese fishing boats detained near Russian-held islands claimed by Japan.