Tension continues on the Korean Peninsula Wednesday as South Korean workers are turned away at the border as they attempt to go to work at the Joint Industrial Zone a mile over the North-South border.

The Kaesong Industrial Complex is the workplace for hundreds of South Korean managers. As they rode to work, they found that they were denied permits to enter North Korea. Permits are approved on a daily basis.

Others that worked in the complex had stayed overnight in North Korea. Of the 800 workers there, about 50 decided to leave on Wednesday. The others have chosen to stay for now. Many are concerned that if they cross the border into South Korea, they will not be able to re-access their workplace. Others were unable to return because the trucks bringing in supplies to the factories were not allowed to cross the border, these trucks were worker’s rides across the border back into South Korea.

The Kaesong Complex is home to about 125 businesses, combined they bring in approximately $2 Billion annually. About 50,000 North Koreans work there.

This new development between the North and South Koreans comes a day after Pyongyang announced that it was re-starting it reactor complex.

In recent week’s, North Korea’s leader, Kim Jong Un has stated that his country is in a state of war with its southern neighbor. He has renounced the 1953 armistace and vowed to make a pre-emptive nuclear strike on South Korea and the United States.

The United States has approximately 28,000 troops in South Korea. The commander of those troops, General James Thurman, is saying the tension there at the border is as tense as he has seen it since taking command in 2011. “The situation is volitile and it is dangerous,” he said.

It isn’t known how long the ban on South Korean workers is going to last, but the factories producing there are a significant revenue resource for the north.

The last time workers at the complex were turned away at the border, was in 2009. That closure too was in response to the annual South Korean-United States military exercises.