MOSCOW, Nov. 1 (Xinhua) -- Russian President Dmitry Medvedev on Monday visited Kunashiri Island, one of the Russian-held islands also claimed by Japan.
Medvedev became the first leader from Russia or the former Soviet Union to travel to any of the disputed islands, which are called the Northern Territories in Japan and the Southern Kurils in Russia.
The islands, where fishery resources are rich, comprise Etorofu (Iturup in Russian), Kunashiri (Kunashir in Russian), Shikotan and Habomai rocks, covering an area of 4,994 square km combined.
These Pacific islands were occupied by Soviet troops in 1945 and are currently under Russian control.
In 1855, Russia and Japan signed a border demarcation treaty, which confirmed that the border lied between Etorofu and Uruppu, explicitly recognizing Etorofu as part of Japanese territory. But the treaty did not mention the Kunashiri and Shikotan islands and the Hobamai rocks.
After Russo-Japanese War of 1904-1905, Japan gained the southern half of the Sakhalin Island from Russia.
In 1945, the Kuril Islands dispute arose in the aftermath of World War II. The Yalta Agreement between the United States, the Soviet Union and Britain stated "the southern part of Sakhalin as well as the islands adjacent to it shall be returned to the Soviet Union" and "the Kuril Islands shall be handed over to the Soviet Union." Again, the agreement did not mention the names of the disputed islands.
In August 1945, the Soviet troops occupied the islands.
In February 1946, the Soviet Union unilaterally claimed the islands as its territory, which was not recognized by Japan.
In October 1956, the Soviet Union proposed to settle the dispute by returning Shikotan and Habomai rocks to Japan until a permanent peace treaty to be signed by both countries.
Yet, the two countries still have not concluded a permanent peace treaty due to the dispute over the islands.
On July 3, 2009, the Japanese parliament passed a law saying the islands were an integral part of Japan. The law was rejected as "unacceptable" by Russia.