Medvedev warned that ceding territory leads to the disintegration of a state, in a sign Moscow was in no hurry to give up the chain as he toured the island of Kunashir which lies just north of Japan s Hokkaido island. "Those who gave away even a small patch of land usually sowed a storm. All of this ends in the collapse of a state," he said in televised remarks. "This is a very dangerous thing." He pledged to improve the lives of the Kurils residents many of whom eke out a threadbare living on the windswept chain. "The farthest region of our state cannot and should not be the most deprived region although this was virtually the case some time ago," Medvedev said. Speaking at a government meeting on Sakhalin Island ahead of his visit to the remote chain, he pledged the government would continue to overhaul the Kurils ramshackle infrastructure, telling his ministers to personally oversee the chain s economic development. "You have to visit the islands although it is not always easy," he said in remarks released by his office, referring to the chain s often mercurial weather.
He also indicated he himself may return. "Three times a charm," Medvedev told the residents of the island where he also inspected a fish-processing plant and a church.
Japan swiftly summoned the Russian ambassador in protest at Medvedev s visit and told him of Tokyo s "extreme regret."
"I take it as something that throws cold water on efforts to build a positive atmosphere in Japan-Russia relations," Foreign Minister Koichiro Gemba separately told reporters.
But his Russian counterpart Sergei Lavrov said the visit should be viewed as nothing out of the ordinary.
"The Russian prime minister was on a scheduled visit in his country and was attending to issues of speeding up the social and economic development of this strategically important region," Lavrov said.
Medvedev s first visit to Kunashir in November 2010 -- when he still held the post of president -- opened long-festering wounds in Japan and sparked a furious reaction from Tokyo which condemned the trip as a "unforgivable outrage".
The two nations have never formally signed a World War II peace treaty because Japan maintains its claim over the islands, which Russia has controlled and tried to develop since Japan s surrender at the end of the war.
Tokyo claims the chain s four southernmost islands, known as the Northern Territories in Japan, and the dispute continues to cast a cloud over Russian-Japanese relations and complicate investment and trade.
The fate of the chain has become the traditional subject of nearly all high-profile talks between Russian and Japanese officials over the past years, with analysts saying those negotiations have reached a dead-end.
Tensions surrounding the Kurils reached new heights after Medvedev s first visit in 2010 that even sparked fears of a conflict.
Russia in February 2011 announced it would boost military defences on the islands.
However, the dispute slackened somewhat after the earthquake and ensuing nuclear accident that shook Japan in March 2011 and prompted expressions of solidarity in Russia.
Home to some 19,000 people, the islands are rich in gold and silver and lie in waters abundant in marine life.
Fyodor Lukyanov, editor of Russia in Global Affairs magazine, expressed bewilderment at the purpose of the visit.
"It is unclear why this is needed now that the Japanese government is signalling that it would like to improve ties with Russia," he said on Echo of Moscow radio.