North Korea said it will partially reopen the border Monday to let South Koreans stranded in the North for three days to return home, an official said.

South Koreans working at factories in the northern border town of Kaesong were stuck in the North at the weekend after officials shut the crossing Friday for the second time in a week amid heightened tensions on the peninsula.

North Korea agreed to let more than 450 South Koreans head home Monday afternoon, Unification Ministry spokeswoman Lee Jong-joo said in Seoul. However, she said North Korean officials are not yet letting workers back into North Korea to enter the sprawling industrial zone to manage the dozens of factories that rely on northern labor to produce everything from clocks to shoes.

The seemingly arbitrary border restrictions have unnerved South Korean business owners who run factories in Kaesong and relying on trucking in raw goods from the South into the impoverished North.

North Korea has provided no official explanation for refusing people entry, but the border shutdowns are the latest in a series of moves by Pyongyang to back off reconciliation with the South.

The two Koreas technically remain at war because their three-year conflict ended with an armistice, not a peace treaty, in 1953. The Demilitarized Zone dividing the foes is one of the world's most heavily armed.

Relations had improved in recent years under two liberal presidents in Seoul, but have dramatically worsened since President Lee Myung-bak took office a year ago. Tensions have further intensified in recent weeks with the North announcing it will send a satellite into space — a launch some fear will be a cover for testing its long-range missile technology.

Most joint inter-Korean projects created during the bloom in relations have been suspended since Pyongyang severely restricted border traffic in December.

Kaesong's factories, which combine South Korean technology and management expertise with cheap North Korean labor, was allowed to operate with a skeleton South Korean staff. But workers and truckers seeking to cross the border need approval from North Korean officials before they can proceed.

The more than 100 factories employing some 38,0000 North Koreans have been a key source of much-needed hard currency for the North.

But one South Korean working at footwear maker Samduk Stafild said by telephone from Kaesong that his factory is having trouble producing goods because of the lack of raw materials recently. He asked not to be named, saying he was not authorized to speak to the media.

South Korea expressed regret over the ban on Sunday. South Korean companies working in Kaesong also pressed the North to normalize border traffic, saying the move had led to a "complete paralysis of business operations" in the complex.