Belligerent utterances from the Democratic People's Republic of Korea are common, but consider this thunderbolt from North Korea army General Officer O Kum-chol. "Soldiers of the Korean People's Army are firmly determined to annihilate the US imperialists, Japanese reactionaries and South Korean puppets at one stroke," he said last week.

"Our People's Army will let loose its pent-up anger and shower thunderbolts of revenge upon the enemies like an angry tiger."

This could be dismissed as rhetoric, the diplomatic tool of a starving nation which has shut itself off from a hostile world, were it not for the fact that the 1.2 million-strong North Korea army is on the move, amid signs that the 1994 nuclear crisis over the Korean peninsula is about to erupt again.

Western correspondents are barred from North Korea but the Chinese press has reported military preparations.

"A new anti-American tide is stirring up all over North Korea," wrote the correspondent of the official Global Times in Beijing. "At political education meetings workers shout `Down with American imperialism'. Citizens say that at the word of their highest commander, Comrade Kim Jong Il, `all of us will go to the front with guns on our shoulders'. "

Seeking an interview with an army commander, the Chinese reporter was told: "Generals at all levels have already gone down to the troops on the front to direct battle preparations."

North Korea's news agency said yesterday the entire population was mobilised, as "students, soldiers and schoolchildren expressed outrage at US war preparations."

Much of this has gone unnoticed in a world preoccupied with crises in Kosovo, Iraq and the Middle East. A much-trumpeted mobilisation by North Korea last year came to nothing. However, worried US, Chinese, South Korean and Japanese officials have been meeting this week to discuss the heightened tension.

The crisis coincides with, and may be explained by, so far inconclusive talks between North Korea and the US in New York over Pyongyang's nuclear programme. In 1994 the United States came close to conflict with North Korea as it ran out of options to dissuade Pyongyang developing nuclear wea pons from plutonium produced by a Sovietera reactor.

The crisis was averted when former US president Jimmy Carter met then-Pyongyang leader Kim Il Sung and arranged a dialogue which resulted in a framework nuclear agreement. Under the deal, Washington and its allies would supply two light-water reactors and 500,000 tonnes of heavy oil annually to North Korea in return for freezing its own nuclear development programme.

North Korea has since accused the US of reneging on its part of the bargain. Washington now wants to inspect a large hole in the ground at Kumchang-ri village, near the site of the old reactor, which it says may be for a new reactor or reprocessing plant. Pyongyang is demanding $300 million (£200 million) for a site inspection, which Washington rejects.

Continued refusals by North Korea to allow free inspections pose serious problems for US policy. North Korea may be trying to play its strongest card, its potential to develop weapons of mass destruction, to gain economic concessions, and its military manoeuvres may be bluff.

However, a South Korean military analyst said North Korea may have decided to walk away from the agreed framework and start reprocessing weapons-grade plutonium.

Chinese officials, well-informed sources say, privately warned US special envoy William Perry when he visited Beijing on Wednesday to go easy with the North Koreans as the country was in a "fragile" state.

Vice-Premier Qian Qichen officially told him: "It is China's consistent stance to maintain the peace and stability on the Korean peninsula" and urged continued dialogue and patient consultation with China's old communist ally. The former US defence secretary proceeded to Tokyo, where he warned that the US may have to scrap the nuclear agreement and that the region was moving towards a critical situation similar to that of June 1994, according to Japanese officials.

American analysts are split between those who believe the North Korean regime is there to stay, despite the famine, and those who say it is a Romania-in-waiting.

The latter view was boosted by the publication this week of a countrywide survey by aid agencies which revealed shocking malnutrition figures after five years of food shortages, indicating that the country needs massive amounts of food and medical aid.

The health service is on the point of collapse, according to the survey, which involved the World Food Programme, the United Nations Children's Fund and the European Union.

This adds a grim note to the sabre-rattling on the last Cold War frontier. Desperate regimes may be tempted to take desperate measures. Underlining the seriousness of the situation, the military magazine, Jane's Intelligence Review, claimed this week that North Korea is making more profound advances in its weapons technology than US intelligence had realised, and that parts of the United States will soon be vulnerable to attack.

It quotes former US Defence Secretary Donald Rumsfeld as saying Pyongyang is now "only a relatively short step from a deployable intercontinental ballistic missile capability".

On August 31st, North Korea horrified its neighbours by launching an extended range Taepodong-1 missile over Japan and into the Pacific Ocean - it claimed to have put a satellite in orbit - and a second trial launch is expected any day.

The weapons are not accurate enough for use against military targets; their real effectiveness is in terrorising a civilian population. The proliferation of missiles carries huge dangers.

In South Korea last week, a fully-armed anti-aircraft missile was accidentally launched 25 miles south of the frontier. It was blown up in mid-air before it got far. Pyongyang seized the opportunity to step up the rhetoric. This was a "planned and provocative move of the South Korean puppets", it said, designed "to unleash a war."