The trip would mark the first time outsiders have been allowed to inspect North Korea's main nuclear facilities at Yongbyon, north of Pyongyang, since the communist country expelled UN nuclear monitors in late 2002.

USA Today first reported yesterday that Washington approved the trip and it was scheduled for January 6-10. The newspaper said the US delegation would include Sig Hecker, director of the Los Alamos National Laboratory from 1985 to 1997. The laboratory produced the first US nuclear bomb.

"The report is true," an official at the South Korean Foreign Ministry said. "The US side has informed us of the trip."

USA Today said the delegation also included a China expert from Stanford University, two Senate foreign policy aides who have previously visited Pyongyang and a former State Department official who has negotiated with North Korea.

Jason Rebholz, a spokesman of the US Embassy in Seoul, said he had no information on the trip and could not comment on the news report.

North Korea is believed to be running a nuclear weapons program at Yongbyon. The United States is trying to persuade the North to give up its nuclear program in return for aid and better ties with the outside world.