“We strongly urge the Russian side to take constructive measures to further advance Japan-Russia relations, including the issue of the conclusion of the peace treaty,” read a statement issued Friday by Japan’s ministry of foreign affairs.
The development came after Medvedev visited one of the four Russian-held islands off Japan’s northern region of Hokkaido. The island is referred to as Iturup in Russian and Etorofu in Japanese.
The foreign ministry statement further described the visit by the Russian prime minister as incompatible with Tokyo’s position on the Northern Territories, insisting that such visits hurt the feelings of the people residing on the island.
Medvedev’s latest visit to the disputed island was his first since 2015 and came despite a request from Tokyo to cancel the trip, according to Russia’s Interfax news agency.
The island is part of the Southern Kurils, known as the Northern Territories in Japan. Tokyo insists they were illegally seized by the Soviet Union following Japan’s surrender at the end of World War II.
The territorial dispute has prevented the two countries from concluding a postwar peace treaty.
Medvedev’s visit is reportedly aimed at highlighting Moscow’s control over the island, through its efforts to develop the remote territory, and comes as bilateral negotiations on the persisting dispute remain deadlocked. According to government officials in Moscow, the Russian prime minister was due to visit a seafood processing factory and a hot-spring facility, check on the progress of upgrading infrastructure such as roads and schools, as well as going fishing on a yacht.
Japan’s Prime Minister Shinzo Abe plans to meet Russian President Vladimir Putin in the Russian city of Vladivostok next month on the sidelines of an economic conference.
Medvedev’s visit, however, may affect plans for joint economic programs on the disputed islands between the two countries, according to Interfax.
Last November, Abe and Putin agreed to accelerate talks on a peace treaty based on a 1956 joint declaration that mentions handing back two of the islands — Shikotan and the Habomai islet group — to Japan.
Further progress, however, has not materialized amid reported concerns by Putin that his declining popularity may sink deeper if he hands over the territory.