Russia's foreign minister has called on Tokyo to accept the outcome of the war in order to advance discussions on a peace plan. Russia and Japan have yet to sign a peace treaty since the end of World War II.
Speaking during an annual press conference, Lavrov said recognizing the outcome of World War II "is neither an ultimatum nor a precondition" for talks.
"It is an inevitable and indispensable factor in today's international system," said Lavrov. "Why is Japan the only country in the world that cannot accept the result of World War II in their entirety?"
At the end of World War II, Japan and Russia did not sign a peace treaty. In 1956, they issued a joint declaration that the then-Soviet Union was willing to cede Shikotan and Habomai, two islands that form part of the disputed Kuril Islands the Red Army captured in the final days of the war.
Last year, Putin and Abe agreed to accelerate talks for a peace deal. Since then, both countries have witnessed protests; in Russia, demonstrators rallied against ceding control of the islands, while in Tokyo, they called on the government to reclaim the territory.