In a move likely to rile Japan, Russia on Tuesday deployed an S-300 airdefense system on the disputed Kuril Islands in the North Pacific.

The system’s readiness was examined by Col. Gen. Gennady Zhidko, theRussian Defense Ministry said in a statement.

The S-300 is meant to protect important sites from air attack, the ministrysaid.

The move will almost certainly provoke a protest from Japan, whichconsiders the Kuril Islands its territories. The territorial dispute overthe islands has not been resolved since World War II.

At the 1945 Yalta Conference, the USSR agreed to start military operationson the eastern front under an agreement with its western allies, and inexchange, received some Japanese territories, including the Kuril Islands.

After the war, however, Japan rejected the Soviet Union’s sovereignty overthe islands.

Due to the dispute, Russia and Japan never signed a peace treaty andtechnically are still at war. As both sides claim the territories, thequestion of the Kurils’ sovereignty remains uncertain.

Tokyo regularly protests visits of Russian officials to the islands.

Russian authorities fear the possible deployment of US missile systems onthe islands if they are returned to Japan, creating a direct militarythreat to Russia.