North Korea on Thursday ordered a military takeover of a factory park that was the last major symbol of cooperation with South Korea, saying Seoul's suspension of operations at the jointly run facility was a "dangerous declaration of war."

Pyongyang said it was immediately deporting the hundreds of South Koreans who work at the complex just across the world's most heavily armed border in the city of Kaesong, pulling out the tens of thousands of North Korean employees and freezing all South Korean assets. The North also said it was shutting down two crucial cross-border communication hotlines.

An immediate worry in Seoul was whether all South Korean workers would be allowed to leave; some analysts speculated that Pyongyang would hold onto some to get all the wages owed North Korean workers.

Some South Korean workers left Kaesong before the North's announcement, and a handful of others were seen leaving afterward, but South Korean officials weren't certain whether all its nationals had departed by Pyongyang's 5:30 p.m. (Seoul time) expulsion deadline, or what would become of anyone who failed to do so.

A manager at a South Korean apparel company at the complex, who declined to give his name, said he and one other South Korean at his company were waiting in an office for word about when they could leave. He said he was not sure whether he would return to the South on Thursday. He said he did not see any North Korean officials and did not know whether other South Koreans were there.

"I was told not to bring anything but personal goods, so I've got nothing but my clothes to take back," the man said.

The South's Unification Ministry, which is responsible for ties with the North, said about 130 South Koreans had planned to enter Kaesong on Thursday to begin shutdown work, and that nearly 70 South Koreans who had been staying there would be leaving.

South Korea's Yonhap news agency, citing an unidentified military official, reported that South Korea bolstered its military readiness and strength along the western portion of the border in the event of a North Korean provocation. The report didn't elaborate on what that meant, and Seoul's Defense Ministry said it couldn't confirm the report.


A security guard directs traffic Thursday as South Korean vehicles transporting employees working at North Korea's Kaesong Industrial Complex, just south of the demilitarized zone separating the two Koreas, in Paju, South Korea. (Kim Hong-Ji/Reuters)

The North's moves, announced by the North's Committee for the Peaceful Reunification of Korea, significantly raised the stakes in a standoff that began with North Korea's nuclear test last month, followed by a long-range rocket launch on Sunday that outsiders see as a banned test of ballistic missile technology. South Korea's responded Thursday by beginning work to suspend operations at the factory park, one of its harshest possible punishment options.

North Korea called the South's shutdown a "dangerous declaration of war" and a "declaration of an end to the last lifeline of the North-South relations." Such over-the-top rhetoric is typical of the North's propaganda, but the country appeared to be backing up its language with its strong response.

North Korea, in its statement, also issued crude insults against South Korea's President Park Geun-hye, saying she masterminded the shutdown and calling her a "confrontational wicked woman" who lives upon "the groin of her American boss." Such sexist language is also typical of North Korean propaganda.

North Korea has previously cut off cross-border communication channels in times of tension with South Korea, but they were later restored after animosities eased.

Seoul said its decision on Kaesong was an effort to stop Pyongyang from using hard currency from the park to develop its nuclear and missile programs.

Earlier Thursday, along the South Korean side of the border, a stream of large white trucks lined up before crossing into North Korea, presumably to bring back products and gear from the factories. Soldiers stood guard near customs offices and military vehicles escorted cars and vans to the South Korean side.

Yoon Sang-eun, 62, a South Korean driver for a firm at the factory park, said that if Kaesong "stops operating, companies like us almost have to close off business. It is difficult."

Factory park has been in operation since 2004

North Korea, in a fit of anger over U.S.-South Korean military drills, pulled its workers from Kaesong for about five months in 2013. But, generally, the complex has long been seen as above the constant squabbling and occasional bloodshed between the rival Koreas, one of the last few bright spots in a relationship more often marked by threats of war.

Park, the South Korean president, has now done something her conservative predecessor resisted, even after two attacks blamed on North Korea killed 50 South Koreans in 2010.

The question among some is, why now?

While Park has yet to explain her reasoning on timing, she has previously shown a willingness to take quick action when provoked by the North. When the North conducted its fourth nuclear test last month, for instance, she resumed anti-Pyongyang propaganda from loudspeakers along the border, despite what Seoul says was an exchange of cross-border artillery fire the last time she used the speakers.

The factory park, which started producing goods in 2004, has provided 616 billion won ($560 million US) of cash to North Korea, South Korean Unification Minister Hong Yong-pyo said.

Combining South Korean initiative, capital and technology with the North's cheap labour, the industrial park has been seen as a test case for reunification between the Koreas. Last year, 124 South Korean companies hired 54,000 North Korean workers to produce socks, wristwatches and other goods worth about $500 million.

The United States supported the move by its close ally, and said it was considering its own, unspecified "unilateral measures" to punish Pyongyang for its recent nuclear test and rocket launch, even as the U.N. Security Council deliberates imposing more multilateral sanctions.

South Korea's government will provide financial compensation to companies that operate at the park, the Finance Ministry said.

South Korean businesses with factories at the park reacted with a mixture of disappointment and anger. In a statement, the association of South Korean companies in Kaesong denounced the government's decision as "entirely incomprehensible and unjust."

Kim Ki-hang, 53, a senior manager with a South Korean company operating at Kaesong, says the government didn't give the companies enough time. "How do we take and ship the products out without enough time?" he asked.

The park also allowed people from both Koreas to interact with each other and glimpse into lives on the other side of the border. Some South Korean snacks have become popular among North Korean workers.

South Korea's government and companies invested more than 1 trillion won ($852 million) to pave roads and erect buildings in the park zone, which lies in a guarded, gated complex on the outskirts of Kaesong, North Korea's third-largest city.