South Korea held massive air-and-grounding drills Thursday to crowds of about 800 in response to North Korea’s deadly artillery attack one month ago. South Korean President Lee Myung-bak said he is planning a “merciless counterattack” if his country is attacked again by North Korea, who responded by denouncing the South as a warmonger. "We had believed patience would ensure peace on this land, but that was not the case," Lee told troops at a forward army unit near the border. About 800 South Koreans watched as the military fired artillery rounds, rockets streamed through the air and F-15s dropped bombs in Pocheon, located about 20 miles from the DMZ. Meanwhile, China—North Korea’s only ally—still tried to urge peaceful dialogue between the Koreas to resolve the latest flare-up.