North Korea has made progress in disabling its main plutonium-producing facilities but failed to complete the work by an end-of-2007 deadline because of technical reasons, Mr Chun Yung Woo told a forum, according to organizers.

Mr Chun and other diplomats have said removing fuel rods from the reactor would take several months and the entire disablement work is expected to be completed by March.

North Korea began disabling its nuclear complex in November, the biggest step the communist nation has taken to scale back its atomic programs.

However, the disarmament procedures have stalled because of a dispute over whether the North missed a Dec 31 deadline to give a full accounting of its nuclear programs.

North Korea has said it already provided the US with a declaration in November, but the US said it was incomplete.

The US State Department's top Korea expert, Mr Sung Kim, flew to North Korea on Thursday in an attempt to resolve the impasse.

There, he met North Korean Foreign Ministry officials and was expected to meet other officials before returning Monday to Washington, US State Department spokesman Sean McCormack said.

'No party is ready to rock the boat over the declaration. It may take some time to work out the difference,' Mr Chun said in prepared comments.

He said a roadmap for North Korea's eventual dismantling of its nuclear programs should be formulated by the end of June, after the current declaration dispute is over, according to the Institute for Far Eastern Studies, which organised the forum.

Mr Chun also suggested that a US-initiated program used in the deactivation of some of the former Soviet Union's nuclear weapons could also be applied to the North Korean nuclear issue.

Under the plan, called the Cooperative Threat Reduction program, the US has provided financial support, equipment and technicians to help the former Soviet Union deactivate nuclear warheads, destroy intercontinental ballistic missiles and chop up nuclear submarines.

Mr Chun stressed the need to redirect nuclear scientists in North Korea to new jobs that would allow them to turn their expertise to the peaceful use of atomic technology.

Mr Chun said there are about 5,000 nuclear scientists in North Korea, according to some estimates. -- AP