South Korean companies operating in the joint Gaeseong industrial complex say pulling out is impossible, in the wake of North Korea's unilateral decision to nullify all related contracts and regulations.

The companies urged the South Korean government to make progress in the proposed working-level meeting with Pyongyang on Monday as they mull countermeasures.

The Association of Gaeseong Industrial Complex Tenant Companies’ Vice Chairman Yu Chang-geun said North Korea is making the threat as it is aware of the losses the companies will have to bear.

The association is planning to hold an emergency meeting to deal with the North’s unilateral demands.