Photo/IllutrationPrime Minister Shinzo Abe, left, meets with Russian President Vladimir Putin in Singapore on Nov. 14. (Takeshi Iwashita)

Prime Minister Shinzo Abe has told Russia's president that Japan would not allow U.S. military bases on two islands off Hokkaido even if Russia returns them based on a 1956 joint declaration, officials from the prime minister's office said.

The Japanese government plans to start concrete talks on the matter with the United States, the officials added.

Abe is seeking to dispel Russian President Vladimir Putin's concern over the potential presence of U.S. bases to promote the return of Habomai and Shikotan, ahead of the two other islands, Kunashiri and Etorofu.

Japan has long demanded that Moscow return all four islands.

The Northern Territories, as they are called in Japan, were seized by Soviet forces at the end of World War II.

The Japan-U.S. Security Treaty and the related Japan-U.S. Status of Forces Agreement (SOFA) stipulate the U.S. forces’ duty to defend Japan, and it can be interpreted that the United States can seek to establish its military bases anywhere in the country.

Russia has expressed strong apprehensions in its negotiations with Japan on the four islands.

When Putin aide and Security Council of Russia Secretary Nikolai Patrushev met with National Security Council secretariat head Shotaro Yachi in November 2016 ahead of a Japan-Russia summit, he asked whether a return of Habomai and Shikotan based on the 1956 document would lead to the establishment of U.S. bases there.

In response, Yachi said, "It's possible," and as a result, the negotiations entered a deadlock.

After that, Abe directly conveyed to Putin that even if Russia returns the two islands to Japan, Japan will not permit U.S. military bases there.

Yachi also conveyed the idea to Patrushev. Shigeru Kitamura, an aide to Abe, also did so to Sergey Naryshkin, director of the Foreign Intelligence Service. Using several routes, the Japanese government has made efforts to dispel Russia's concern.

Regarding the Japan-U.S. Security Treaty and SOFA, a high-ranking Japanese Foreign Ministry official said: "The U.S. forces can seek to establish bases anywhere in Japan. But whether Japan gives its consent is another matter."

Based on this view, Japan plans to discuss the matter with the United States while pursuing negotiations with Russia. But it remains unclear whether the United States will cooperate, as the country is in conflict with Russia over such issues as the crisis in Ukraine, a civil war in Syria and Russia's suspected meddling in the 2016 U.S. presidential election.