Former Prime Minister Yoshiro Mori revealed Sunday that Japan and Russia agreed during working-level talks in early April to set up two frameworks regarding the return of Russian-held islands at the center of a decades-old bilateral dispute.

One of the two frameworks will cover conditions for returning the Habomai group of islets and Shikotan Island, while the other will deal with the fate of the other two islands, Kunashiri and Etorofu, Mori said on a TV Asahi program.

The agreement was reached during talks in Moscow between Japan's Kazuhiko Togo, then head of the Foreign Ministry's European Affairs Bureau, and Russian Deputy Foreign Minister Alexander Losyukov, following talks between Mori and Russian President Vladmir Putin in Irkutsk in late March, Mori said.