Russia on Monday strongly rejected remarks by Chief Cabinet Secretary Yoshihide Suga questioning Russian sovereignty over four islands controlled by Moscow but claimed by Tokyo.
Suga last week said Japan will be flexible on the timing of the return of the islands off east Hokkaido if the two countries ever agree that they belong to Japan.
Russian Foreign Ministry representative Maria Zakharova, while stating that Suga had basically repeated Japan's official position on the islands, effectively warned against seeking concessions beyond those stipulated by the 1956 Japan-Soviet joint declaration, under which the former Soviet Union agreed to hand over two of the four islands to Japan after the conclusion of a peace treaty.
Former Prime Minister Yoshiro Mori, who is scheduled to visit Russia next month as a special envoy of Prime Minister Shinzo Abe, said at the beginning of this month that Russia's returning three of the islands will be one option for resolving the long-standing territorial row.
The islands of Etorofu, Kunashiri and Shikotan, as well as the Habomai islet group, were seized by the Soviets in August 1945 after Japan's surrender at the end of World War II. The dispute has prevented Japan and Russia from ever concluding a peace treaty.
Zakharova repeated Russia's stance that Moscow's sovereignty over the islands is based on the legally formalized results of World War II, and a solution of the territorial dispute should be sought against the background of the current state of relations between the two countries.