MOSCOW (Reuters) - Russia said on Tuesday it had deployed a number of its new S-300V4 missile defence systems for combat duty on a disputed chain of islands near Japan, a move that is likely to anger Tokyo. The Russian Defence Ministry’s Zvezda TV station said the mobile air defence system designed to counter ballistic and aerial attacks was on Iturup, one of four islands held by Russia that Japan claims and calls the Northern Territories. “Short-range anti-aircraft missile systems are already on duty on the island of Iturup in Sakhalin Region. Now the air defence ‘heavy artillery’ has arrived. The so-called large air defence system: the S-300V4,” Zvezda said. The Soviets seized the islands, known as the Southern Kuriles, at the end of World War Two and a territorial row over them has prevented the two sides signing a formal peace treaty since and strained relations for years. Japan is highly sensitive to military moves by Russia on the strategically important chain of islands that stretch northeast from Japan’s Hokkaido to the Russian Far East region of Kamchatka. Russia said in October it planned to deploy the missile system on the islands for the first time, but that the move would be part of military drills and not for combat duty. The deployment comes not long after former Japanese Prime Minister Shinzo Abe, who mounted a push to resolve the dispute and tried to win over Russian President Vladimir Putin, announced he was stepping down in August.