Russia is planning to deploy additional missile systems on two islands in the northern portion of the Kuril Islands chain off Hokkaido in a bid to strengthen its defense capabilities in the region, an internal Russian government document showed Monday.

The document, obtained by Kyodo News, revealed that a new land-to-ship missile system called the Bastion, which has a range of more than 300 kilometers, would be deployed on Paramushir and Matua in the chain, which also includes four Japan-claimed islands.

The plan indicates that Russia places strategic importance on the Kuril Islands in defending the Sea of Okhotsk and its nuclear forces against the United States.