Updated

China and Russia are holding their largest-ever joint naval drills in the Sea of Japan in a sign of warming ties between the former Cold War rivals.

Eighteen surface ships, one submarine, three airplanes, five ship-launched helicopters and two commando units are taking part. The "Joint Sea-2013" exercise begins Friday and runs through July 12.

The drills are considerably bigger than anything China's navy has held with a foreign partner. China's increasingly formidable navy is contributing four destroyers, two latest-generation guided missile frigates and a support ship.

China has long been a key customer for Russian military hardware, but only in the last decade have their militaries begun training jointly. China's armed forces are pursuing links with most regional militaries.