North Korean leader Kim Jong Un ordered his front-line military troops into a “semi-war state” Friday, hours after his country exchanged artillery fire with South Korea. According to North Korean state news agency KCNA, Kim ordered military units of the Korean People’s Army to “enter a wartime state” and asked troops to be “fully battle-ready to launch surprise operations.” The decision was made at an emergency meeting for the central military commission, of which Kim is chair, late Thursday, KNCA reports. The meeting came amid mounting tension between the North and South, which traded fire over a speaker blasting anti-North Korean propaganda near the border. North Korean gave Seoul 48 hours to shutter the speaker or face military action. The offer expires at 5 p.m. Saturday.