Explainer: 65-year dispute over Kuril archipelago
Why do a group of islands with bad weather matter so much to Japan and Russia. We look at the origins of the dispute which has led to a diplomatic spat.
The Soviet Union seized the Kuril Islands on 8 August 1945 just after Japan had surrendered to the US at the end of the Pacific War. Moscow had only declared war on Japan six days before the end of the conflict and after the atomic bomb was dropped on Hiroshima.
Japan had controlled all the1,300-kilometre-long volcanic archipelago since 1855 and refers to it as its Northern Territories.
The two countries have never signed a peace treaty to formally end World War II hostilities, largely due to the disputed islands.
The climate is harsh and the population is about 19,000 but the islands have mineral deposits, including gold and silver, and rich fishing grounds. They were home to Soviet air and sea bases during the Cold War.
The Soviet Union moved the 17,000-strong Japanese population to Kazakhstan and Uzbekistan.
In 1956 Moscow offered to give back the two smallest islands but Japan rejected the idea.
After the collapse of the Soviet Union talks on improving ties have resumed but no progress has been made, mainly because of the Kurils dispute.
The European Parliament backed Japan in 2005, calling on Moscow to hand back the islands.
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