North Korea ratchets up nuclear tensions

North Korea heightened tensions over its nuclear weapons programme today with a tirade against Western criticism and a threat of war against South Korea.

The North also apparently restarted its weapons-grade nuclear plant a day after conducting its second nuclear test explosion.

It called South Korea’s decision to join an operation to prevent the spread of weapons a declaration of war.

Its state news agency said it would respond with military action if South Korea tried to stop or search any of its ships as part of a US-led Proliferation Security Initiative.

“Those who provoke (North Korea) once will not be able to escape its unimaginable and merciless punishment,” the news agency said.

Meanwhile, South Korea’s mass-circulation Chosun Ilbo newspaper reported that US spy satellites detected signs of steam at the North’s Yongbyon nuclear complex, an indication that it may have started reprocessing nuclear fuel.

The move would be a major setback for efforts aimed at getting North Korea to disarm.

North Korea had stopped reprocessing fuel rods as part of an international deal. In 2007, it agreed to disable the Yongbyon reactor in exchange for aid and demolished a cooling tower at the complex.

The North has about 8,000 spent fuel rods which, if reprocessed, could allow it to harvest 13 to 18lbs of plutonium – enough to make at least one nuclear bomb, experts said.

North Korea is believed to have enough plutonium for at least a half dozen atomic bombs.

It has also test-fired five short-range missiles over the past two days and suggested more could be planned.

The moves have brought a wave of international reproach.

In New York, the UN Security Council is discussing a resolution that could include new sanctions.

Ambassadors from the five permanent veto-wielding council members – the United States, Russia, China, Britain and France – as well as Japan and South Korea are expected to meet again soon to work out the details.

Council members, after condemning the test on Monday, said they would follow up with a new legally binding resolution.

China and Russia, both allies of North Korea, slammed it for going ahead with the blast.

Moscow’s UN ambassador, Vitaly Churkin, who is also the Security Council president, said the 15-member body would begin work quickly on a new resolution.

China also said it “resolutely opposed” the nuclear test. But it was unclear how far it would go in sanctions against its neighbour.

Experts said past sanctions have had poor results because they were not fully implemented and because North Korea is already one of the most isolated countries in the world.