Japan's Foreign Ministry says Russian authorities have seized four Japanese fishing boats in disputed waters off Russia's far east on suspicion of illegal fishing.
The ministry said Saturday that the boats were intercepted and searched by Russian officials off Kamchatka peninsula, and have been taken to the Russian port of Petropavlosk-Kamchatskii.
Earlier this year, a Russian border patrol fired on a Japanese fishing boat in the disputed waters, killing a fisherman before seizing the vessel and the remaining three crew members.
The incident increased already tense relations over the four Kuril islands, which were seized by Soviet troops at the end of World War II, and are still claimed by Japan.
The dispute over the islands has prevented the two countries from signing a peace treaty officially ending the war.
Some information for this report was provided by AFP and AP.