Japan has sent a note of protest to Russia over the country’s recently announced plans to deploy troops to the disputed Kuril Islands, the RIA Novosti news agency reported.
Increasing Russia's military presence on the islands, which Moscow and Tokyo both claim sovereignty over, would be "regrettable," Yoshihide Suga, general secretary of the Japanese government, said at a press conference.
"This is contrary to the position of our country," he added.
The latest dispute in the longstanding Kuril controversy began on Wednesday, when Russian Defense Minister Sergei Shoigu said during a speech at the State Duma that Russia "was continuing active work to defend the Kurils."
Shoigu added that Russia "should deploy a division" there this year.
Japan, which lays claim to the southern Kuril Islands, considers their return a precondition for signing a post-World War II peace treaty with Moscow. But Russia believes its claims to the Islands are supported by international treaties.
Russia has significantly increased its military presence on the Kuril Islands recently. In March 2016, Shoigu announced Russia would deploy top-of-the-line Bal and Bastion coastal defense systems — with ranges of up to 450 kilometers — as well as the new Aeleron-3 drones to the islands.
In December, Japan mulled allowing U.S. military bases on two of the southern islands during a meeting with Russian Security Council Head Nikolai Patrushev.