North Korea said it had slowed down work to disable its plutonium-producing complex at Yongbyon in protest at delays by its negotiating partners the United States, South Korea, China, Russia and Japan in delivering promised energy aid.

'The US last week procured an additional 50,000 metric tons of heavy fuel oil (HFO) for the DPRK (North Korea),' State Department deputy spokesman Robert Wood said in a statement.

'That HFO will arrive in North Korea on two different ships in late November and early December 2008,' he added.

Mr Wood said the United States will have provided 200,000 tons of HFO to North Korea once the shipment is completed.

'As of today, China, the Republic of Korea, Russia, and the United States have provided a total of approximately 500,000 tons of energy assistance, including HFO and non-HFO equivalent energy assistance,' he added.

The State Department said last month it had contacted a number of countries - US officials privately identified them as Australia and European Union countries - about supplying fuel oil to North Korea after Japan refused.

Japan wants North Korea to do more to account for Japanese kidnapped by the communist state in the 1970s and 1980s to train its spies before it supplies fuel to Pyongyang under the 2007 disarmament deal.

The Japanese refusal raised fears that the nuclear disarmament talks could stall.

North Korea, which tested an atomic weapon in October 2006, said in a statement carried by the official Korean Central News Agency that it had cut by half the rate at which it removes spent fuel rods from the Yongbyon reactor.

'In case the economic compensation continues to be delayed, the tempo of the disablement will be decreased accordingly, making it hard to predict the prospect of the six-party talks,' the statement said on Wednesday. -- AFP