South Korea has proposed talks with North Korea over a stalled joint factory complex, and is warning of a tough response if Pyongyang does not respond within 24 hours.
The South Korean Unification Ministry did not say what Seoul would do if Pyongyang does not respond to the offer by the Friday morning deadline, but it threatened "grave action" if the offer is rejected.
Operations at the Kaesong industrial complex, just north of the border, have been suspended since North Korea angrily pulled its workers and blocked South Korean access to the center earlier this month.
About 180 South Koreans remain there in hopes that production can resume, but they are thought to be quickly running out of food and supplies. Some say if the impasse is not resolved soon, Seoul may be forced to pull the workers out.
Kaesong is the last remaining symbol of cooperation between the two foes, and is seen as a bellwether of Korean relations. Although work a the center has been suspended during times of heightened tensions, it has never been shut down completely since it was established in 2004.
Though Pyongyang has refrained from making daily threats of violence against the South in recent days, tensions remain high on the Korean peninsula.
North Korea is angry over United Nations Security Council sanctions passed in response to its February nuclear test, as well as annual joint military exercises between South Korea and the United States.