Following a series of bellicose threats, North Korea warned it could shut down the Kaesong Industrial Complex in protest of the ongoing Seoul-Washington joint war games.

Located in the city of Kaesong in North Korea, the complex is the last remaining example of inter-Korean cooperation from the Sunshine Policy days, and business has been going on as usual.

The Central Guidance to the Development of the Special Zone, a North Korean bureau in charge of the cross-border complex, said in a statement Saturday if there was “any attempt to damage the dignity” of the country, it will “ruthlessly shut down” the complex.

The threat came after South Korean media reports cast doubt on the North ever shutting the complex, a main cash cow for the regime to earn U.S. dollars.

According to the South’s Ministry of Unification, the 2012 revenue for the North from the Kaesong complex was about $80 million.

Pyongyang tried to flip that reasoning Saturday, saying the reason it kept the complex going was not for itself, but for South Korean companies running factories there.

“Those who benefit from the complex are the South’s small companies,” the statement said. “The fate of the Kaesong complex depends on the attitude of the [South’s] government.”

North Korea said on Wednesday it had cut all hotlines between Seoul and Pyongyang.

Since Pyongyang ratcheted up its threats against Washington and Seoul, it was the first time it threatened to shut down the complex.

Currently, all information regarding the complex is communicated through international phone calls or fax messages. The complex operated on Saturday as usual, and about 310 South Korean workers were working there yesterday.

The South Korean government said in a statement that the threat wasn’t new.

“The threat to shut down the Kaesong complex is considered a kind of follow-up measure to the threat of going to ‘combat readiness posture No. 1,’?” the South Korean government said. “We don’t see those repeated threats as helpful to the development of inter-Korean relations.”

The government said it will still “operate the complex stably” and that the safety of South Korean workers is “the top priority.”

On the same day, North Korea also declared “a state of war” with the South.

In a “special statement in the name of the administration, the party and civic groups,” it said once a war broke out, it would “develop into a nuclear war” to attack the continental U.S. and its overseas bases, and also strike all of South Korean territory within three days.

South Korea’s Defense Minister Kim Kwan-jin said at a workshop with politicians Saturday that if the North staged any attacks, the South’s military would “bring weapons not only from U.S. bases overseas but also from the U.S. mainland” for retaliation.

As threats from the North grew, a group of South Korean businessmen appealed to the government not to shut the Kaesong complex down.

“Please stop all the time-consuming political debates for the development of the Kaesong Industrial District and inter-Korean relations,” Han Jae-kwon, a South Korean businessman running factories making handkerchiefs and scarves, said at a luncheon with reporters yesterday.

“If the complex is shut down, it would make at least 15,000 people jobless and damage a lot of affiliated companies, not only the 123 companies in the complex,” he said.

According to the Unification Ministry, the complex has a total of 123 South Korean companies and 54,234 workers, 786 from the South.

By Kim Hee-jin [heejin@joongang.co.kr]