"The trip is useful," Kim Sung, head of the eight-member team, told reporters before leaving the airport in Pyongyang. He is also head of the Korean Affairs office of the US State Department.
He refused to release any further details about the trip.
The team arrived here last Thursday as the first step of US efforts to lead the disablement of North Korean nuclear facilities as agreed in a joint document released on October 3 by the second session of the sixth round of the six-party talks which was held in Beijing, China.
A second US team will arrive here later this week for further negotiations on disabling atomic facilities, according to the US State Department.
North Korea agreed to disable all its existing nuclear facilities and to provide a complete and correct declaration on all its nuclear programs by the end of this year, according to the October 3 joint document.
The disablement of the 5 megawatt experimental reactor at Yongbyon, the reprocessing plant (radiochemical laboratory) at Yongbyon and the nuclear fuel rod fabrication facility at Yongbyon will be completed by December 31, 2007, according to the document.
As agreed, the US would lead the disablement activities and provide the initial funding.
The six parties -- China, North and South Korea, the US, Russia and Japan -- signed a landmark agreement on February 13 which required North Korea's complete and correct declaration of all its nuclear programs. The agreement also asked the other five parties to provide a total of 1 million tons of heavy fuel oil or equivalent aid to North Korea in return.