North Korea has threatened South Korea with widespread military strikes unless it halts cross-border propaganda. Pyongyang also threatened the US with nuclear attack over planned US-South Korea maneuvers.
North Korea threatened Saturday to attack its southern neighbor after activists launched helium balloons carrying anti-Pyongyang leaflets.
The communist nation also said it would attack loudspeakers set up by South Korea to broadcast across the border, a practice restarted after 11 years after three of its soldiers were seriously injured in landmine explosions earlier this week. North Korea denies responsibility.
"The puppet forces should not forget even a moment that the whole of South Korea might turn into a sea of fire due to the foolhardy leaflet-scattering operations," the North's Korean People's Army said. "There is a limit to the patience of the frontline soldiers of the KPA."
US-South Korea military exercise
Nuclear-armed North Korea also turned its rhetoric against the US, which is planning to join South Korea on Monday to begin two weeks of military drills and war games that simulate an invasion by North Korea.
The North's National Defense Commission threatened Washington with the "strongest military counter-action" should the joint exercise proceed.
The North Korean army and people "are no longer what they used to be in the past when they had to counter the US nukes with rifles," the commission said in a statement.
It is now an "invincible power equipped with both latest offensive and defensive means ... including nuclear deterrence," it said.
Inflammatory language from Pyongyang isn't unusual and it's not the first time North Korea - whose artillery is capable of striking South Korea's capital - has warned it would reduce its neighbor to a "sea of fire."
Both the US and South Korea were threatened with nuclear annihilation in the months after leader Kim Jong Un took power in 2011.
70th anniversary of liberation
The nuclear threats and bitter recriminations come at a time when both Koreas are set to commemorate the 70th anniversary of the peninsula's liberation from Japan following the end of World War Two.
There had been hopes the anniversary would be an opportunity for some sort of inter-Korean rapprochement. Instead relations have spiralled downwards to the familiar accompaniment of ominous threats and mutual recrimination.
jar/bk (AP, AFP, dpa)