North Korea yesterday renewed threats to launch a "sacred war" against South Korea, indicating cross-border ties will remain icy despite Pyongyang's surprise nuclear deal with Seoul's close allyWashington.

The North's agreement to freeze some nuclear and missile activities in return for massive US food aid has raised cautious hopes of eased tensions under its new young leader Kim Jong-Un.

In statements released late Wednesday announcing the deal, both Pyongyang and Washington pledged to work for better relations.

But Friday's comments from the North's supreme military command struck a different tone with the South.

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)", it said in a statement on the official news agency.

The command vowed to "mercilessly" wipe out anyone who "slightly insults and defames" the dignity of the North's supreme leadership.

Pyongyang made similar threats last year when 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.

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

Under the 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 readmit UN nuclear inspectors.

The United States said it would provide the impoverished and hungry

country with 240,000 tonnes of food intended for young children and pregnantwomen.

Analysts said Wednesday's deal could help revive the six-party talks, but many remain sceptical that the North will abandon its nuclear weaponry.

North Korea's pledge to suspend uranium enrichment, as well as nuclear and long-range missile tests, has received a cautious international welcome.

A White House spokesman called it a "positive first step" towards denuclearising the Korean peninsula.

China and Russia also welcomed the move, while Japan said it could "be seen as progress".

China, North Korea's sole ally, has welcomed the deal and pledged to push ahead with efforts to revive the wider nuclear dialogue.

Washington had also called on Pyongyang to improve ties with Seoul, although the State Department made no mention of this in its statement Wednesday.