South Korea's land and sea exercises prompted North Korea, which has threatened to reduce the South to ashes on many occasions, to denounce its richer neighbor as a warmonger.

"To counter the enemy's intentional drive to push the situation to the brink of war, our revolutionary forces are making preparations to begin a sacred war at any moment necessary based on nuclear deterrent," North Korea's KCNA news agency quoted Minister of Armed Forces Kim Yong-chun as saying.

State Department spokesman P.J. Crowley said "we need constructive actions, not heated rhetoric" from Pyongyang.

"The last thing the region needs from North Korea is more threatening rhetoric," he said in Washington. North Korea has wielded its nuclear capability threat before but analysts say it has no way to launch a nuclear device. [ YAHOO NEWS ]