n Tuesday to survey the communist country's main nuclear complex ahead of Pyongyang's promised disablement of facilities so it cannot produce bombs. The seven-member delegation crossed into the north by land from the border village of Panmunjom around 11 a.m. (0200 GMT), said David Oten, spokesman for the U.S. military in South Korea.
They will join two nuclear experts from China and Russia who plan to fly to Pyongyang for a joint survey.
During a five-day visit, the three-nation team plans to visit North Korea's main nuclear complex at Yongbyon, 100 kilometers (60 miles) north of Pyongyang, to examine ways of disabling facilities there under a February international accord.
The North has already shut down the country's sole functioning nuclear reactor at Yongbyon under the deal that also calls for Pyongyang to disclose all its nuclear programs and disable its facilities in exchange for economic aid and political concessions.
In recent bilateral talks with the U.S., the North promised to complete the disablement by year's end.
The North's invitation of outside nuclear experts _ the first since July when U.N. nuclear inspectors verified the shutdown of the Yongbyon reactor _ is considered a strong indication Pyongyang is serious about following through with its denuclearization commitments.
On Monday, the head of the U.S. delegation, State Department official Sung Kim, met with South Korea's deputy nuclear negotiator Lim Sung-nam to discuss the trip.
The two sides agreed "the steps for disablement should be implemented in an effective and speedy manner," Lim told reporters.
Lim said the trip would not result in an agreement on how to disable the facilities, as the experts were only there to survey the sites and get an idea of the actions needed to dismantle them.
The experts would deliver their findings at the next round of six-nation talks, when an agreement on disabling the facilities was likely, he said.
The six nations - the two Koreas, the U.S., Japan, Russia and China - agreed at their last meeting in July to meet again in September.
The February deal came after more than three years of on-again, off-again negotiations during which North Korea conducted its first-ever nuclear test detonation in October.
