North Korea is backpedaling on a nuclear disarmament agreement and has started to reassemble its main nuclear complex in a threat to undo years of negotiations with the United States and other nations.

The North said it will rebuild its facilities at Yongbyon after taking steps to disable the nuclear reactor and related facilities. In a show of cooperation earlier this year, North Korea destroyed a cooling tower at the reactor.

The North justified its reversal with a claim that the United States has not removed the country from its blacklist of terrorist nations. That was promised after Pyongyang made a declaration of its nuclear programs as called for in an agreement last year with the United States, China, Russia, Japan and South Korea.

However, the Bush administration rejected the claim, noting that North Korea had not agreed to plans for inspections to determine if the declarations or accounting of nuclear activities was complete.

Such inspections and verification are essential to know whether the secretive nation has made a complete disclosure and to learn if the North had produced any nuclear weapons.

One Bush administration official, though, noted it would be hard to rebuild the reactor at this stage of dismantling.

North Korea's threat cannot be taken lightly, but based on its past actions, the United States and partner nations must see to it that the North be held to the agreement with verifiable inspections.