Russian Foreign Minister Sergei Lavrov on Thursday will visit one of the Japanese-claimed Habomai islets east of Hokkaido, sources said Tuesday.
Lavrov plans to include Suisho Island on his tour of the disputed islands, along with Kunashiri and Shikotan.
Suisho Island is called Tanfilyev Island in Russia.
The uninhabited islet is just 7 km from Nosappu Point on Hokkaido's eastern tip.
Japan has long demanded that Russia return Etorofu, Kunashiri, Shikotan and the Habomai islets to its control. The islands were seized by the Soviet Union at the end of World War II.
Lavrov's planned visit to Suisho Island apparently reflects Moscow's determination to maintain its grip on all of the disputed islands, the sources said.
The foreign minister is scheduled to fly to Kunashiri Island, and then visit Shikotan and Suisho islands, the sources said.
President Vladimir Putin's representative for the Russian Far East, Kamil Ishakov, toured Suisho Island by helicopter in March. In June 2005, Federal Security Service Director Nikolai Patrushev visited the island.