BEIJING, June 28-- Recently, the Hong Kong Garrison of the People's Liberation Army (PLA) has launched a combat training exercise participated by its naval, army and air forces. On land, the combined-arms battalions involving signal corps, armored forces and artillery forces came into cooperation; at sea, the guided-missile frigates Suqian (Hull 666) and Jingmen (Hull 667) carried out training on more than ten subjects of land-to-sea operations, air and missile defense (AMD), etc.