South Korean workers' departure to an inter-Korean industrial complex in North Korea's Kaesong was being delayed on Wednesday, as the North has yet to give approval to their cross-border trip, officials here said.

The delay came after Pyongyang has threatened to shut down the Kaesong Industrial Complex and launch a pre-emptive nuclear war on Seoul and Washington over South Korea-U.S. joint military drills and U.N. sanctions for its latest nuclear test.

Officials at the Customs, Immigration and Quarantine Office in Paju, about 50 kilometers northwest of Seoul, said that the North Korean side was not authorizing the daily trip of South Korean managers and cargo over the Demilitarized Zone (DMZ) that separates the two Koreas.

They said 179 South Korean workers and 153 vehicles that were scheduled to cross the border around 8:30 a.m. were waiting for permission from the North. For the entire day, a total of 484 South Koreans and 371 vehicles are scheduled to go to Kaesong.

Despite the delayed passage, the Kaesong Industrial District Management Committee said that South Korean plants at the North Korean border town were operating normally.

At present, there are 868 South Korean workers staying at the Kaesong complex, home to 123 labor-intensive factories. The complex, the crowning achievement of the 2000 inter-Korean summit meeting, also employs some 54,000 North Korean workers. (Yonhap News)