Beijing, Jan. 30 -- Recently, vessels attached to a combat support ship flotilla of the PLA Navy, together with the guided-missile destroyer Zhanjiang and the naval aviation troops, carried out high-intensity and integrated operational support drills around the clock for continuous days in waters of the South China Sea. The drills involved training courses of gun shooting, replenishment-at-sea, takeoff and landing of ship-borne helicopter, etc., which effectively tested the troops' ability to coordinate and deal with emergencies.