The delegation, including senior US diplomat Sung Kim, will visit the Yongbyon nuclear reactor, which is slowly being disabled in accordance with an agreement struck in February, they said.
"We are pretty positive. I think we are making progress," Kim told journalists before departing Beijing along with officials from China, Japan, Russia and South Korea.
The team of officials, the first multinational delegation to travel to North Korea as part of the disarmament process, is expected to stay there for three days.
At the same time South Korea's defence chief left Tuesday for rare talks with his North Korean counterpart on easing border tensions to clear the way for multi-billion dollar reconciliation projects.
Defence Minister Kim Jang-Soo was scheduled later Tuesday to start three days of talks in Pyongyang with his counterpart Kim Il-Chol.
The defence ministers' meeting will be only the second in the history of the two countries, which have remained technically at war since their 1950-1953 conflict ended only in an armistice.
China's official Xinhua news agency, one of the few foreign media groups allowed to have a base in North Korea, said the officials arrived in Pyongyang on Tuesday afternoon.
Kim will also meet up with the team of eight US experts at Yongbyon who have been in and out of North Korea on a rotating basis since early October as part of the inspection process, a US embassy spokeswoman in Beijing told AFP.
North Korea agreed in the landmark accord reached in February with the other five nations to disable its nuclear programmes in exchange for much-needed energy aid and diplomatic benefits.
Pyongyang has agreed to disable Yongbyon, the source of the plutonium used in the North Korea's first-ever atomic test in October 2006, by the end of this year. Disabling means ensuring it can not be restarted for many months.
It must also declare by the end of the year all of its nuclear programmes, before completely and irreversibly disarming.
Disablement of the five megawatt Yongbyon reactor began in early November.
Another round of the six-nation talks is expected to be held in Beijing next month, but so far no specific dates have been announced.
The US envoy to the six-nation talks, Christopher Hill, was due to depart the United States on Tuesday for a trip to South Korea, Japan and China to discuss the disarmament process, officials in Washington said.
Güncelleme Tarihi: 27 Kasım 2007, 12:28