Seoul  - North Korea said Monday that it would allow hundreds of South Koreans stranded at a joint industrial park for three days to leave the country.

But Pyongyang was still balking at allowing South Korean commuters to travel back and forth over the heavily guarded inter-Korean border to the park at Kaesong, the Unification Ministry in Seoul said.

A travel ban would threaten the industrial park, which was started as a reconciliation project between the two neighbours, who are still technically at war after a ceasefire but not a peace treaty ended the 1950-53 Korean War.

Initially, 453 of the 725 South Koreans stuck in Kaesong were expected to return Monday to South Korea, a ministry spokeswoman said.

North Korea on Friday blocked the workers' entrance and exit to Kaesong for a second time in a week.

Earlier, the Stalinist country's Korean People's Army had put its troops on combat alert in protest of this month's joint military exercises conducted by the United States and South Korea, which the North sees as a prelude to an invasion.

In addition, Pyongyang cut the last remaining telephone line with the South, which it generally allowed the South Korean workers in Kaesong to use.

The line is to remain cut until the end of the annual joint military manoeuvres, planned Friday.

The halt to commuter traffic to Kaesong threatens production at the majority of factories at the park because shipments of raw materials have also not been allowed from the South.

More than 35,000 North Korean workers are employed at the complex by more than 90 South Korean companies. Among the products they produce in the impoverished country are shoes, clothing, clocks and cooking equipment. (dpa)