evidence: Called the Kurils by Russia and the Northern Territories by Japan, a string of volcanic islands are at the heart of a feud between the two countries that has prevented them signing a formal World War II peace treaty. [...] Russian Empress Catherine the Great claimed sovereignty over the Kuril islands in 1786 after her government declared they were discovered by "Russian explorers" and therefore "undoubtedly must belong to Russia". [...] The Kuril islands have been back at the centre of a dispute between Moscow and Tokyo since Soviet troops invaded them in the final days of World War II.