China's defence ministry said Thursday that it was in talks with Russian counterparts about joint military exercises next year, after Moscow announced drills were planned for the Mediterranean Sea and Pacific Ocean.

Chinese defence ministry spokesman Geng Yansheng told reporters at a monthly briefing that China and Russia were "conducting consultation" over next year's joint military exercises.

But after Russian defence minister Sergei Shoigu visited Beijing last week, Moscow's defence ministry said in a statement: "New joint naval exercises are planned next spring in the waters of the Mediterranean Sea.

"Joint exercises are also planned in the Pacific Ocean."

The prospect of joint exercises by the two military powers in the Mediterranean is likely to raise eyebrows in Europe given what is seen there as increased muscle-flexing by Russia after it annexed Crimea and supported rebels in eastern Ukraine.

US General Philip Breedlove, NATO's top military commander, said Wednesday he was "very concerned" that Russia's military build-up in the annexed Crimean region could be used as a launchpad for attacks across the whole Black Sea region.

Geng, who was asked about Moscow's announcement, noted that China and Russia have conducted "numerous joint exercise" both bilaterally and under the Shanghai Cooperation Organisation, which groups the two countries along with several Central Asian states formerly part of the Soviet Union.

"These joint exercises have become institutionalised and a routine occurrence," he said.

"For the two countries to conduct joint military exercises will help to improve both countries' capability to deal with security challenges and maintain regional peace and stability," he said.