Russian Foreign Minister Sergei Lavrov and his Japanese counterpart, Taro Kono, said after a meeting in Moscow that much effort is still needed before their countries can resolve a World War II-era territorial dispute that stands in the way of a peace agreement.
Ahead of the May 10 talks, Russia's Sergei Lavrov said "extremely significant" differences remained between Moscow and Tokyo's positions, despite several previous rounds of negotiations.
A dispute over four islands between the Sea of Okhotsk and the Pacific Ocean -- known as the Northern Territories in Japan and the Southern Kuriles in Russia -- seized by the Soviet Army at the end of World War II, has prevented Moscow and Tokyo from formally ending their wartime hostilities, with Japan refusing to recognize Moscow's sovereignty over the archipelago.
"The task is not easy. It's clear it will only be solved by long, painstaking, and creative work," Lavrov told the press following the meeting.
"Solving a problem that remains unresolved more than 70 years on from the end of the war is not easy," Kono said at a joint news conference, in remarks translated into Russian. "It cannot be said that as a result of today's talks we were able to overcome these differences."
A further meeting between the foreign and defense ministers of the two countries will be held at the end of May in Tokyo, Lavrov said.
Prime Minister Shinzo Abe and President Vladimir Putin have made resolving the dispute a priority, meeting 25 times since 2013.
But they face public opposition to any compromise and at a meeting in Moscow in January fell short of reaching an agreement.
In January, Putin said after talks with Abe that "painstaking work" remains before Moscow can conclude a peace treaty with Tokyo, adding that any settlement that negotiators might propose must be "supported" domestically.
Russia in recent months has taken further steps to consolidate its hold on the islands, which are home to some 20,000 people, building new military facilities there in December, and laying fiber-optic cables for high-speed Internet access.