BEIJING - Three naval ships of China's Nanhai Fleet left a naval port in Sanya, Hainan province, on Wednesday, kicking off an annual combat drill in the South China Sea and neighboring waters.

The three ships include missile destroyer Hefei, missile frigate Sanya and supply ship Honghu. They will later be joined by missile destroyers Lanzhou and Guangzhou, as well as missile frigate Yulin, which are now carrying out other duties.

With three helicopters and dozens of "special warfare" soldiers, the fleet will be separated into three groups that will sail to areas of the South China Sea, the east Indian Ocean and the west Pacific, to conduct varied drills.

The fleet will mobilize naval air force, garrison forces in the Xisha and Nansha islands, and forces of the Beihai Fleet along the way to take part in the drill.

The drill aims to enhance combat readiness and practise coordination between ships and aircraft, and other forces, the navy said.