TOKYO, March 19. /TASS/. Russian President Vladimir Putin and Japanese Prime Minister Shinzo Abe spoke over the phone on Monday to discuss a peace treaty and joint economic activity on in the south of the Kuril Islands, the Japanese Foreign Ministry reported.

"The leaders discussed the peace treaty issue, joint economic activity on four northern islands (Northern Territories is the way Japan refers to the Southern Kurils) and humanitarian measures for former [Japanese] residents of these territories," said the report Tass has received.

Moscow and Tokyo have been for decades engaged in consultations with an aim to hammer out a peace treaty to end WWII. The ownership of the southern part of the Kuril Islands is the main obstacle. After the war, the archipelago became part of the Soviet Union, but Japan challenges the ownership of Iturup, Kunashir, Shikotan and Habomai islets. However, the Russian Foreign Ministry has repeatedly stated that the Russian sovereignty over them is unquestionable under international law.

The sides see joint economic activity on these islands as a move towards signing a peace treaty. However, as Japanese observers have stressed, they so far differ as to how these projects should be carried out. Russia believes this should be done within the framework of its legislation, while Japan suggests creating a certain ‘special system’ on the above territories.