Russia's president has visited a group of disputed islands claimed by both Russia and Japan, drawing criticism from the Japanese prime minister.

Dmitry Medvedev became the first Russian leader to visit the Kuril Islands on Monday.

The islands, which lie north of Japan's Hokkaido island, have been controlled by Moscow since they were seized by Soviet troops at the end of World War II, but Tokyo claims the southernmost four as Japanese territory.

Al Jazeera's Adrian Finighan looks at the origins of the dispute which has led to a diplomatic spat.