A major fire Thursday at a building used by Russia’s Federal Security Service (FSB) left one person dead and two others injured, according to reports. Flames tore through the building in the city of Rostov-on-Don—less than 75 miles from the Ukrainian border—before being contained by emergency services. The building was occupied by the FSB’s border patrol section, with Rostov regional governor Vasily Golubev saying the blaze broke out after a “short circuit in the electrical wiring inside the premises.” The FSB later released a statement saying the fire began in the repair shop where “fuel and lubricants” ignited, causing “an explosion and partial destruction of the building.” The incident is one of dozens of mysterious fires to erupt in Russia since the invasion of Ukraine began.