The North hates the military drills, which run until late April and which analysts say force its impoverished military to respond with expensive deployments and drills of their own. An unidentified spokesman for the North's General Staff of the Korean People's Army said last week that Pyongyang's reaction to the southern drills would be the toughest ever but didn't elaborate The United States has 28,500 troops stationed in South Korea, and 50,000 in Japan, as a deterrent against a potential aggression from the North.