The fire broke out on Friday evening at the national information resources service in Daejeon, a major technology hub 140km (87 miles) south of Seoul. The facility is one of three operational government datacentres managing critical digital infrastructure across the country.

Workers were relocating lithium-ion batteries from a fifth-floor server room to the basement for replacement when one ignited, with the fire spreading to other batteries and adjacent servers. One worker sustained first-degree burns, and firefighters extinguished the fire after 22 hours.

By Saturday morning, officials had shut down 647 government systems fearing further damage. Government email and intranet systems ground to a halt. Mobile identification services went dark, as did postal banking, complaint portals, and major government websites.