SEOUL (Reuters) - North Korea’s military threatened on Tuesday to use everything in its arsenal to reduce South Korea to rubble unless Seoul stops civic groups from sending anti-Pyongyang leaflets into the communist state.

North Korean soldiers clap their hands at an undisclosed location in North Korea in a picture released by KCNA on August 16, 2008. REUTERS/KCNA

The North has lashed out at the South’s president who took office in February for his pledges to get tough with his neighbor and has been enraged by a fresh wave of propaganda leaflets sent by balloons launched in the South in recent months.

“We clarify our stand that should the South Korean puppet authorities continue scattering leaflets and conducting a smear campaign with sheer fabrications, our army will take a resolute practical action as we have already warned,” the official KCNA news agency quoted the military spokesman as saying.

At a rare round of military talks on Monday, North Korea complained about the leaflets while South Korean activists sent a new batch of 100,000, despite warnings from Seoul not to do so.

“The puppet authorities had better bear in mind that the advanced pre-emptive strike of our own style will reduce everything opposed to the nation and reunification to debris, not just setting them on fire,” the spokesman said.

South Korean groups have been sending the leaflets into the North for years. Analysts said the recent wave appeared to have touched a nerve because they mentioned a taboo subject in the North -- the health of leader Kim Jong-il.

U.S. and South Korean officials have said Kim may have suffered a stroke in August, raising questions about who was running Asia’s only communist dynasty and making decisions concerning its nuclear arms program.

North Korea mostly refrained from threatening the South when it was receiving a steady stream of unconditional aide under liberal presidents who ruled for 10 years before President Lee Myung-bak.

But it has unleashed a torrent of insults at Lee, who wants to tie handouts to progress the North makes in nuclear disarmament, calling him a traitor to the nation. About six months ago, it threatened to reduce the South to ashes.

Some experts said the onslaught of rhetoric might signal that the North’s patience was running thin and it could start a skirmish with the South, without launching a full-scale strike.

“North Korea could seize on a small accident or unintended intrusion on land or at sea and escalate it into a localized military clash, which would ultimately pose a serious security threat on the Korean peninsula as a whole,” said Koh Yu-hwan, an expert at Dongguk University in Seoul.

The leaflets sent on Monday were printed in water-proof ink on plastic sheets and carried the names of South Korean civilians and prisoners of war believed to be held in the North as well as a family tree the civic groups said maps Kim’s relationships with several women who bore him children.

A North Korean defector now leading the leaflet campaign in the South, Pak Sang-hak, said he had no plans to stop sending the airborne messages.

He said North Koreans were unaware of Kim’s actual personal life, which makes Pyongyang’s propaganda apparatus worried about anything that cuts into the cult of personality it has built for its “Dear Leader.”