In a statement on Saturday, Russia’s Ministry of Defense said, between October 17 to October 23, Russian and Chinese warships held joint exercises in the Western part of the Pacific ocean, in their first ever joint patrol.

Earlier in October, China and Russia staged naval cooperation drills in the Sea of Japan. In recent years, Moscow and Beijing have curated closer diplomatic and military ties following souring relations with the West.

Japan kept a close eye on their naval manoeuvres. Earlier this week, Japan said, a group of 10 vessels from China and Russia sailed through the Tsugaru Strait separating Japan’s main island and its northern island of Hokkaido.

“The group of ships passed through the Tsugaru Strait for the first time as part of the patrol,” said the Russian defence ministry in a statement.

The strait is regarded as international waters.

The Russian Ministry went on to add, “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”.