BEIJING--Four Chinese navy ships have departed for joint drills with Russia in the latest sign of growing cooperation between the two militaries.

The official Xinhua News Agency says a destroyer, missile frigate, supply ship and submarine rescue ship departed Wednesday from the port of Qingdao, home to China's north sea fleet.

Xinhua said the drills are being held in the Sea of Japan near the Korean Peninsula and the Sea of Okhotsk off the northern Japanese island of Hokkaido.

The exercises are the second stage of an annual joint drill, the first part of which was held July 22-27 in the Baltic Sea--the first time the countries have exercised together in the northern European waterbody.

Russia and China are closely aligned on many diplomatic and security issues.