SEOUL - SOUTH Korea expressed its deep concern on Wednesday at North Korea's decision to bar UN inspectors from its Yongbyon plant and to reintroduce nuclear material.

'The government is very concerned about North Korea's continued move to restore nuclear facilities in Yongbyon,' the foreign ministry said in a statement.

'The government urges North Korea to resume work on disablement at an early date and actively cooperate for an agreement on the verification protocol.'

'The government is paying keen attention to the situation and is in close cooperation with other countries involved in six-party negotiations'.

The North had earlier announced it was restarting its plutonium-producing Yongbyon complex in protest at the US failure to remove it from a terrorism blacklist.

The United States refuses to do so until the North allows strict outside inspections to verify a nuclear inventory which it handed over in June as part of a six-country disarmament deal.

The International Atomic Energy Agency (IAEA) said on Wednesday the North had told its inspectors to remove seals and surveillance equipment.

The North said it plans to introduce nuclear material to the reprocessing plant, which produces plutonium from spent reactor fuel rods, in one week's time, and barred the inspectors from the plant. -- AFP