North Korea on Wednesday abruptly cancelled an invitation to United Nations Secretary General Ban Ki-moon to visit the isolated state.
Ban said "no explanation was given for this last-minute change.'' He called the decision "deeply regrettable."
The U.N. chief was planning on Thursday to visit a factory park that lies just north of the demilitarized zone that separates North and South Korea.
Ban's planned tour of the jointly run Kaesong Industrial Complex would mark the first time in more than two decades that a U.N. secretary-general has visited North Korea.
The last head of the international body to visit the North was Boutros Boutros-Ghali, who crossed through the DMZ in 1993.
Announcing the visit Tuesday, Ban called the factory park a "win-win model for both Koreas."
"I reiterate my willingness to do whatever it takes to contribute to improving inter-Korean relations and promoting reconciliation and stability on the Korean peninsula," said Ban, who arrived in Seoul on Monday.
He was expected to meet with North Korean workers and South Korean businessman during the trip to Kaesong. More than 53,000 North Korean workers are employed by about 120 South Korean factories in the park.
The facility was established in 2004. It serves as one of the few areas of cooperation between North and South Korea, which remain in a state of war since their 1950s conflict ended in a truce rather than a peace treaty.