The North has accused South Korea of slandering Pyongyang's top leaders [Reuters]

North Korea has renewed threats to launch a "sacred war" with South Korea, indicating cross-border ties will remain icy despite Pyongyang's agreement to freeze some nuclear and missile activities in return for 240,000 tonnes of US food aid.

Friday's comments from the North's supreme military command struck a different tone with the South after statements announcing Wednesday's deal, saw pledges from both the North Korean and US capitals to work towards better relations.

The command accused South Korean troops of displaying slogans or placards slandering the North's top leaders at their barracks, shooting ranges and other military facilities.

The soldiers "openly slandered and defamed the dignity of the supreme leadership of the DPRK (North Korea) after creating a touch-and-go situation", it said in a statement on state media.

The command "solemnly declares once again that it will indiscriminately stage its own-style sacred war to wipe out the group of traitors,

"Those who hurt the dignity of the supreme leadership of the DPRK even a bit will find no breathing spell in this land and sky," it said.

Last year saw similar threats from Pyongyang after South Korean reservists were found to be using pictures of the ruling Kim dynasty as rifle-range targets. The South says that practice has been stopped.

Pyongyang has taken a consistently hostile tone towards Seoul since Jong-Un took over after his father Kim Jong-Il died of a heart attack in December.

Last Saturday it threatened a "sacred war" over US-South Korean joint military drills, describing them as a "silent declaration of war".

The North has vowed to never deal with the South's conservative leaders, accusing them of trying to spark a war and rejecting appeals for dialogue.

On Friday North Korea described their neighbour as "a mad dog getting more ferocious before meeting its end".

Finalising food aid

Under the North's agreement with the United States, the communist state promised to suspend a uranium enrichment programme and declare a moratorium on nuclear and long-range missile tests. It would also re-admit UN nuclear inspectors.

The United States said it would provide the impoverished and hungry country with food aid intended for young children and pregnant women.

On Friday the US State Department said US and North Korean officials will meet next week in Beijing to finalise plans for the food aid.