The move comes hours after a UN Security Council committee on Friday placed three North Korean companies on a UN blacklist. The companies stand accused for aiding Pyongyang's missile and nuclear programmes.

North Korea was swift to react with announcing to reactivate its nuclear program. A government spokesperson told the country's state run news agency that "the reprocessing of spent fuel rods from the pilot atomic power plant began as declared in the Foreign Ministry statement."

The development comes after Pyongyang walked out of international nuclear disarmament talks earlier this month in a response to a UN decision to punish it for a controversial rocket launch.

North Korea claims it put a satellite into orbit in what was widely regarded as a disguised long-range missile test. The UN Security Council regarded the launch as a breach of a UN resolution and threatens sanctions.

North Korea on April 14 reacted to the criticism by announcing it would quit six-nation talks and restart its atomic weapons programme. The North had been disabling parts of its Yongbyon nuclear complex as agreed under a February 2007 six-nation deal involving South Korea, the US, China, Russia and Japan.

Experts say it could take the country, which conducted its only nuclear test in October 2006, as little as three months to have the reprocessing facility up and running again.