Nine Russian and Chinese navy vessels gathered in the Mediterranean Sea for joint military drills that will go on until May 21.

Nine Russian and Chinese navy vessels gathered in the Mediterranean Sea for joint military drills that will go on until May 21, the Russian defense ministry said on Sunday.

The first joint military exercises by the two countries in the region come amid high tensions between Russia and the West over Ukraine and as China is increasingly assertive in pursuing territorial claims at sea.

The ministry said a headquarters for the exercises had been set up aboard the Russian missile cruiser Moskva, which belongs to the Black Sea Fleet with its base in Crimea, the peninsula Moscow annexed from Kiev in March 2014.

It quoted Vice-Admiral Alexander Fedotenkov, a deputy commander of the Russian navy who is leading the exercises from the Russian side, as saying the 'Sea cooperation - 2015' drills were "not aimed against a third country."

"The goal is to strengthen mutual understanding between the navies... regarding boosting stability, countering new challenges and threats in the sea," Fedotenkov said.

Moscow has stepped up military drills as ties with the West have deteriorated over the crisis in Ukraine, triggering criticism from NATO.

Russia says it must protect its interests in the face of a growing role of the military alliance in the region.