TOKYO, Nov. 2 (UPI) -- Tokyo and Moscow have entered into a war of words over the first visit by a Russian president to the disputed Kuril Islands.
Russian President Dmitry Medvedev visited the Kuril Islands Monday and met local residents in Kunashir, the second largest of the four islands and pledged more investment in the region.
His trip immediately caused a reaction in Tokyo where the Japanese Prime Minister Naoto Kan called Medvedev's visit regrettable and Russia's envoy was summoned. Russia's Foreign Ministry said in a brief statement that Japan's reaction to Medvedev's trip to the Kuril Islands was "unacceptable."
Kunashir Island is one of the four Russian-held islands off Hokkaido that Japan wants returned.
Japanese Foreign Minister Seiji Maehara summoned Russian Ambassador to Japan Mikhail Bely to the ministry to file an official protest over the president's trip. Maehara reportedly told the ambassador that the Russian president's visit "is in conflict with Japan's principle position and hurts the Japanese public sentiment."
But Bely later said that Medvedev's visit was a domestic issue.
"I said that this visit is purely Russia's domestic issue ... and there is no overseas or international aspect," Bely said. "I called on the Japanese side to deal with this matter calmly and with balance."
Since the end of the second world war, all of the islands have been under Russian jurisdiction but Japan claims the four southernmost islands as part of its territory.
The volcanic archipelago of 56 islands and dozens of rocky outcrops stretches for more than 800 miles, from the southwest tip of Russia's Kamchatka Peninsula to the eastern edge of Japan's northern Hokkaido Island. The chain nominally separates the Sea of Okhotsk from the northern Pacific Ocean.
The largest and most northerly is Iturup Island, around 120 miles long and up to 15 miles wide. Kunashir Island, the second largest -- 80 miles by 15 miles – is also the closest of the four islands to Hokkaido.
Around 40 of the 100 volcanoes are still active and earthquakes of magnitude 8 and more on the Richter scale aren't uncommon. The weather is wet and foggy in summer and cold and snowy in winter.
The entire island chain is sparsely populated, with fewer than 17,000 people -- mainly shipped-in ethnic Russians, Ukrainians, Belarusians and Tatars, as well as some surviving original inhabitants, the Ainu.
Just more than 17,000 Japanese people lived on the four southern islands before the Soviet occupation and eventual expulsion of the Japanese to Japan.
Fishing is the main occupation and around half the inhabitants of all the islands live below the poverty line.
But what makes the islands strategically important are the larger commercial fishing rights as well as mineral deposits including pyrite, sulfur and other ores.
At the heart of the dispute is a lack of a peace treaty between the former World War Two enemies. In 1956 the Soviet Union agreed to cede the two of the four islands -- Habomai and Shikotan -- to Japan following a presumed peace treaty. But a treaty has never been signed and the all four occupied islands remain disputed territories, according to Japan.
Japanese officials warned Medvedev's visit could hinder bilateral economic ties, an issue that he and his Japanese counterpart likely will have to discuss at the Asia-Pacific Economic Cooperation summit in Yokohama this month.
The Russia-Japan dispute over the Kurils is Tokyo's second major international territory issue within two months. Relations between China and Japan were strained by a row over another island group -- known as Senkaku in Japan and Diaoyu in China -- in the South China Sea and which both countries claim as their territory.
In early September Japanese patrol boats detained a Chinese fishing boat in the area, and after it allegedly rammed the two Japanese vessels during its escape bid. The sailors, captain and boat were eventually returned to China.