North Korean leader Kim Jong-un ordered his frontline troops onto a war footing Friday to Back-up an ultimatum for South Korea to halt high decibel propaganda broadcasts across the border or face concerted military action. The move came as military tensions on the divided Korean peninsula soared following a rare exchange of artillery fire on Thursday that put the South Korean army on maximum alert. Kim chaired an emergency meeting late Thursday of the North’s powerful Central Military Commission (CMC) which endorsed the ultimatum for the South to switch off its propaganda unit loudspeakers by Saturday afternoon. According to the official KCNA news agency, Kim ordered frontline, combined units of the Korean People’s Army (KPA) to “enter a wartime state” from Friday 5:00pm (0830GMT). The troops should be “fully battle ready to launch surprise operations ” while the entire frontline should be placed in a “semi-war state,” KCNA quoted him as saying. The South Korean Joint Chiefs of Staff responded with a direct message to the KPA, urging it to refrain from any “reckless acts” and warning that it would react strongly to any further provocation. Technically, the two Korea’s have been at war for the past 65 years, as the 1950-53 Korean conflict ended with a ceasefire that was never ratified by a formal peace treaty.