Japan Concerned over Russia-China Military Cooperation: Foreign Ministry

"In the military sphere, (Russia’s) cooperation with China has increased, including the passage of (Chinese and Russian) naval vessels sailing together (July to August) and joint patrols (involving) attack aircraft (June and December)," the report reads. "In terms of Japanese security, the increased joint activities between China and Russia around Japan are a cause of concern and need to be closely monitored," the Japanese Foreign Ministry said, TASS reported.

The Russian Foreign Ministry has repeatedly emphasized previously that similar drills and patrols are held in strict compliance with international law and exclude any violations of foreign airspace.

In turn, China has demanded that Japan stop taking useless measures that hamper its joint patrols with Russia in the region. Also, Beijing has stressed that, during such air patrols, China and Russia adhere to international law.