Japanese Prime Minister Kishida Fumio says his government will continue making efforts to settle a territorial issue with Russia.
Kishida spoke at a nationwide meeting in Tokyo on Wednesday. The event is held annually to mark Northern Territories Day and call for the return of the four islands.
A Japan-Russia treaty signed on February 7, 1855, recognized that the islands belong to Japan.
Russia controls the islands. Japan claims them. The Japanese government maintains the islands are an inherent part of Japan's territory. It says the islands were illegally occupied after World War Two.
Kishida said it is regrettable that the territorial issue has still not been resolved and that a peace treaty has not been signed even though 78 years have passed since the war ended.
He said his government will continue to pursue these goals, even though Japan-Russia relations have been negatively affected by Russia's aggression in Ukraine.
The prime minister noted that the resumption of bilateral exchange programs is one of his government's top priorities in Japan-Russia relations.
One program allows former Northern Territories islanders to visit the graves of their family members. He said his government wants to fulfil the ardent hopes of the former islanders, who are advancing in age, and will continue urging Russia to resume the exchanges.
The participants pointed out that the Northern Territories issue has been impacted by current international relations, and called the current state of the four islands "illegal occupation" by Russia.
A statement was adopted at the meeting appealing for the return of the islands with efforts to be made by both private and public sectors.