South Korean and U.S. troops were on high alert Thursday after the reclusive North Korean regime signalled its unwillingness to co-operate with international demands to dismantle its nuclear program.
The isolationist nation said it was preparing for an American-led attack and would meet any hostility with "merciless" and dangerous ferocity.
"The northward invasion scheme by the U.S. and the South Korean puppet regime has exceeded the alarming level," the North's main Rodong Sinmun newspaper said in a commentary on Thursday.
"A minor accidental skirmish can lead to a nuclear war."
The U.S., which has 28,500 troops in South Korea and another 50,000 in Japan, has said it has no plans to attack.
Meanwhile, South Korea moved a 3,500-ton destroyer into waters near the disputed western maritime border it shares with the North.
Pyongyang has positioned artillery guns along the west coast of its side of the border.
Tensions have been high since the isolationist regime carried out an underground nuclear test earlier this week as well as a number of short-range missile tests.
On Wednesday, Pyongyang ended the truce that was put in place in 1953 to end of the Korean War. The regime warned that any naval action against its ships would be seen as an act of war.
Former United Nations weapons inspector Hans Blix said North Korea's actions seem designed to maintain tension and keep the nation isolated from the world.
"I'm beginning to wonder if the military side, the hardline military side wants to have certain controversy going with the outside world because that can help to justify their military control and justify the misery the population is in," Blix told CTV's Canada AM.
In addition to fears about North Korea's nuclear capability there are also concerns the nation could sell its technology to a terrorist group, or that Japan could seek nuclear armament in order to defend itself if necessary, Blix said.
"If that were to happen then the temperature in the Far East would go up very drastically and relations with China would be very much impaired," Blix said.
"So the conclusion from that is that China itself would have very strong reasons to calm North Korea and make them come back to six-party talks and to a settlement."
As a result of the tests, more than 90 nations agreed to stop and inspect vessels that could be carrying banned weapons to the peninsula.
Pyongyang reacted quickly to the news of the international community's response, claiming the Proliferation Security Initiative led by Washington -- and Seoul's participation in it -- is nothing more than a prelude to a naval blockade.
South Korea's foreign ministry spokesperson Moon Tae-young said the decision to participate in the security initiative has been distorted by Pyongyang, calling the reaction "a groundless misconception."
The joint South Korean-U.S. forces have raised surveillance levels to the highest they have been since 2006, when North Korea carried out its first nuclear test.
With files from The Associated Press
