Russian state media reported that Putin visited Iturup, known in Japan as Etorofu, one of four islands in the Kuril chain that are claimed by Russia and Japan. Putin's trip “has worsened Japanese sentiment towards Russia”, Takaichi told reporters, maintaining the island chain was "a unique territory of Japan historically and under international law". The countries have been locked in a dispute over the Kurils for decades, and it is the main reason Moscow and Tokyo did not sign a peace treaty after World War Two. The Kuril islands sit between Hokkaido in northern Japan and Russia's Kamchatka Peninsula. Four of the southernmost islands are claimed by Japan, which calls them the Northern Territories. They are administered by Russia. At the end of World War Two, the Soviet Union annexed the island chain and deported around 17,000 Japanese residents. During his visit, Putin sampled fish roe and spoke to island locals, Russian state media reported. Speaking from the prime minister's office on Thursday, Takaichi said his trip "wounds the feelings of the Japanese people" and is "incompatible with Japan's consistent position on the Northern Territories".  "I hope that the Russian side will take the gravity of this matter very seriously”, she said. Earlier that day, Japan's foreign minister Toshimitsu Motegi said the islands were "inherently Japanese territory both historically and under international law, and the Government of Japan strongly protests this visit". (BBC)