Russian Prime Minister Dmitry Medvedev on Friday visited one of the four Pacific islands disputed between Russia and Japan, to the disappointment of Tokyo.

Medvedev visited the Island of Iturup known as Etorofu in Japanese, one of the four islands called Southern Kurils in Russia and the Northern Territories in Japan.

Visits like Medvedev's are incompatible with Japan's position on the Northern Territories and hurt the feelings of the Japanese people, the Japanese Foreign Ministry said Friday.

Russia, however, dismissed the Japanese statement. "This is our land. This is a subject of the Russian Federation," Medvedev said at a press conference on the island, according to an official transcript.

Moscow and Tokyo have failed to sign a postwar peace treaty due to their rival claims to the four islands.

According to a joint declaration signed in 1956, the then Soviet Union agreed to return two of the islands on condition that a bilateral peace treaty was signed, which was rejected by Japan, the pre-war owner of the islands.

Russian President Vladimir Putin and Japanese Prime Minister Shinzo Abe agreed during their meeting last November in Singapore to start peace talks based on the 1956 joint declaration.

No significant progress has been made so far despite several rounds of talks.