MOSCOW, Dec 21 (Reuters) - A submerged Russian submarine has successfully launched a Kalibr cruise missile from the Sea of Japan at a target more than 1,000 kilometres (621 miles) away, located at a Russian training ground onshore, the RIA news agency said on Tuesday.

The drill also involved covert movement and support from military ships, aircraft and drones, it quoted Russia's Pacific Navy as saying.

Japan lays claim to the Russian-held southern Kuril islands in the nearby Sea of Okhotsk, which Tokyo refers to as the Northern Territories in a territorial row dating from the end of World War Two, when Soviet troops seized them from Japan.

The dispute has prevented the two countries from signing a formal peace treaty.