THE White House has warned North Korea that hostile behaviour does nothing to ease its isolation or feed its people, after Pyongyang's military threatened to turn parts of Seoul to "ashes."

North Korea's military yesterday made an extraordinary threat of "special actions" soon to turn parts of the South Korean capital to ashes, accusing Seoul's conservative government of defaming its leadership.

The North said its targets were "the Lee Myung-Bak group of traitors, the arch criminals, and the group of rat-like elements including conservative media destroying the mainstay of the fair public opinion".

It said the actions "will reduce all... to ashes in three or four minutes... by unprecedented peculiar means and methods of our own style".

media_camera A North Korean vehicle carrying a missile passes by during a mass military parade in Pyongyang's Kim Il Sung Square to celebrate the centenary of the birth of the late North Korean founder Kim Il Sung. The enormous, 16-wheel truck used to carry the missile, likely came from China in a possible violation of U.N. sanctions meant to rein in Pyongyang's missile program, experts say. Picture: AP

The North has for months been criticising the South's President Lee Myung-Bak in extreme terms and threatening "sacred war" over perceived insults.

There have been no incidents but the language has become increasingly vitriolic. Some analysts said they believe a military provocation is likely.

"The special actions of our revolutionary armed forces will start soon to meet the reckless challenge of the group of traitors," a statement on the official news agency said.

Tens of thousands rallied in Pyongyang last Friday, screaming hatred for Lee and calling for his death over alleged insults.

media_camera North Korean soldiers chant at Kim Il Sung Square in central Pyongyang, North Korea, during a rally denouncing South Korean President Lee Myung-bak. Picture: AP

Last week the nuclear-armed North bridled at comments by Lee and conservative media which questioned the cost of the anniversary celebrations and failed rocket launches.

Lee said the estimated $850 million cost of a rocket launch nine days ago could have bought 2.5 million tonnes of corn.

White House spokesman Jay Carney would not react specifically to the North Korean threat of "special actions" in the coming days, but he said he could not rule out more provocative behaviour from the Stalinist state.

"Provocative behavior by the North Korean regime does nothing to feed its people. In fact, it does the opposite," Mr Carney said.

"It does nothing to grow that economy. In fact, it does the opposite.

"It does nothing to reduce the isolation of that regime from the rest of the world. In fact, it does the opposite."

North Korea has also warned of retaliation after the United States scrapped a deal for food aid over the failed rocket launch earlier this month by Pyongyang.

Some experts believe that the North, as Kim seeks to establish his power, may soon conduct another underground nuclear test.

The North staged atomic weapons tests months after its long-range rocket launches in 2006 and 2009, which also earned UN condemnation.

US President Barack Obama visited the demilitarised zone between the two Koreas last month and denounced the isolated and impoverished state as a nation which cannot make "anything of any use" and "doesn't work".

Originally published as 'We will reduce Seoul to ashes within minutes'