Russia and Japan sparred on Saturday over disputed islands that have strained their relations since World War II, making no visible progress in talks toward a resolution weeks before Russia hosts a summit of Asian states.
Japan wants Russia to hand over four islands at the southern end of the Kuril chain that were occupied by Soviet forces at the end of the war in 1945, saying they are Japanese territory.
Moscow disagrees, and senior Russian officials have drawn protests from Japan in the past two years by travelling to the Pacific islands, which Russia calls the Southern Kurils and Japan calls the Northern Territories.
Tension over the issue was palpable beneath the diplomatic language at a joint news conference following talks between Russian Foreign Minister Sergei Lavrov and his Japanese counterpart, Koichiro Gemba, who also met President Vladimir Putin in the Black Sea resort of Sochi.
"It is very sad that 67 years after (World War Two) the territorial issue is still not resolved," Gemba said, speaking through an interpreter.
"I believe that amid conditions of serious changes in the strategic situation in the Asia-Pacific region, the need to resolve this problem is becoming greater and greater," he said in an apparent reference to China's growing might.
Lavrov rejected Japanese criticism of trips by officials including Dmitry Medvedev, who made the first visit to the islands by a Russian president in 2010 and went there again on July 3, this time as prime minister
"We cannot accept the protests that have been heard from Tokyo about this," Lavrov said. "Russian authorities are responsible for improving the socioeconomic situation in this part of the Russian Federation and we will continue to do this."
Russia has dedicated new funds and political attention to the country's vast but sparsely populated Far East in advance of an Asia Pacific Economic Cooperation (APEC) summit in the coastal city of Vladivostok in September.
Lavrov said Japan's protests over the visits "do not help create the conditions for normal dialogue" on the dispute, which he said should be held "in a calm atmosphere without whipping up emotions and without artificial historical interpretations."
Gemba said he had conveyed Japan's regret over Medvedev's trip to Kunashir, one of the islands, which lies 15 km (10 miles) from the Japanese island of Hokkaido.
Putin and Gemba did not mention the islands in comments, with reporters present, at the start of their meeting.
Putin focused on economic and energy cooperation and asked Gemba to thank the head of Japan's Akita Prefecture for the gift of a puppy that Gemba's delegation delivered to Russia.