The two countries, which staged naval manoeuvres together in the Sea of Japan earlier this month, have forged closer military and diplomatic ties in recent years as relations with the West have deteriorated.
The naval exercise has been closely watched by Japan, which said earlier this week that a group of 10 vessels from China and Russia had sailed through the Tsugaru Strait, separating Japan's main island and its northern island of Hokkaido, into the western Pacific.
The middle of the 100-mile stretch of sea, which is between 15 to 25 miles (24 to 40 km) wide, is regarded as international waters.
Japan's territorial waters in the area reach just three miles off shore, rather than the normal 12 miles.
This dates back to a Cold War agreement, to enable nuclear-armed US warships and submarines to transit the strait without violating Japan's ban on the weapons in its territory.
Russia's defence ministry said in the statement said: “The group of ships passed through the Tsugaru Strait for the first time as part of the patrol.
“The tasks of the patrols were the demonstration of the Russian and Chinese state flags, maintaining of peace and stability in the Asia-Pacific region, and guardianship of the subjects of maritime economic activities of the two countries.”Internet Explorer Channel Network