A flotilla madeup up of ships from China’s Nanhai Fleet set sail on Monday from a military port in south China’s Hainan Province for a drill in the South China Sea, according to military sources.

The drill, part of annual exercises, includes combat exercises in the West Pacific Ocean and the east Indian Ocean. The three-ship flotilla consists of amphibious landing craft Changbaishan and the destroyers Wuhan and Haikou. Three helicopters and a company of land forces are aboard the ships.

Fleet commander Jiang Weilie said the drill will focus on testing the combat ability of lead ships, submarines and aviation forces while exploring methods for open sea drills.