Two South Koreans returned home Sunday from the South Korea-run industrial complex in the North Korean border town of Kaesong after one of them became ill, officials here said.

Sunday marks the fifth day since North Korea began blocking South Korean workers and cargo from entering the Kaesong complex.

"We had a patient at the complex, which prompted a total of two people, including a driver, to cross the border into the South by car through the Dorasan Customs, Immigration and Quarantine (CIQ) office in Paju, Gyeonggi Province," the Unification Ministry said in a statement.

There was no home-bound trip scheduled for Sunday.

The return brought the number of South Koreans in the Kaesong complex down to 514, which is twice the number of South Koreans in the border town on weekends when business is normal. There are also four Chinese workers in the Kaesong complex.

A total of 39 South Koreans and 21 vehicles are scheduled to return home on Monday. If the plan proceeds as scheduled, it will bring the number of South Koreans in the complex to 475.

The 43-year-old surnamed Ha requested an emergency home-bound trip, complaining of stomachache at about 5 a.m. and arrived at the Dorasan CIQ at about 7:40 a.m.

After being taken to the emergency room of a hospital in Goyang City, just north of Seoul, Ha received treatment for chronic gallbladder disease.

Ha was dispatched from the hospital at 12:40 p.m. to receive a surgery at his hometown in Chungcheong Province.

As North Korea last week blocked the supply of raw materials and food to factories in Kaesong, nine more companies there halted operations on Sunday, according to government officials, bringing to 13 the total number of South Korean firms that have closed down over the recent threats from North Korea.

As many as 123 firms have built factories in Kaesong to produce light industry goods using cheap North Korean labor.

More companies are expected to follow suit if the North's entry ban continues.

The two Koreas signed an agreement on creating the complex in 2000, and the groundbreaking followed three years later. The first goods were produced for market in 2004. The South has invested 900 billion won ($802 million) into Kaesong so far with combined output reaching $2.01 billion.

Pyongyang had earlier threatened to shut down the complex, accusing Seoul of "insulting the dignity" of the North's leadership by saying Pyongyang was in no position to shut down the industrial park despite escalating tensions because of its status as a source of badly needed foreign currency for the cash-strapped North.

North Korea in recent weeks unilaterally nullified the Armistice Agreement that halted the 1950-53 Korean War while announcing it will no longer respect a nonaggression pact with South Korea. (Yonhap News)