The eight experts, led by the head of the State Department's Korea desk, Sung Kim, were due to launch the process of disabling the North's reactor at Yongbyon, which produces bomb-grade plutonium, US officials said earlier.

Xinhua, one of the few foreign media organisations allowed to have a presence in North Korea, said the team had arrived in Pyongyang on Thursday afternoon on a flight from Beijing.

North Korea agreed last week to disable by December 31 the main reactor at Yongbyon and two other key nuclear facilities at the complex, which were shut down in July in the first phase of a February six-nation disarmament accord.

As part of last week's agreement, the United States was tasked with overseeing the disablement of the facilities.

North Korea is also required by the end of the year to make a full declaration of its nuclear network under the deal clinched by China, the United States, Russia, the two Koreas and Japan.

North Korea, which conducted its first test of an atomic bomb last year, was promised energy aid as well as diplomatic and security guarantees in return for ending its nuclear weapons programme.