At least 73 people were killed in Johannesburg when a fire broke out at a dilapidated building used by homeless people, authorities said Thursday. A local government official said some people living in the five-story building in the center of South Africa’s biggest city had thrown themselves out of windows in an effort to escape the flames, which may have accounted for some of the deaths. Emergency services say seven children—including a 1-year-old—were among those killed. Another 55 people were hurt in the blaze that erupted at around 1 a.m. It’s not yet clear how the fire started. Johannesburg Emergency Services Management spokesman Robert Mulaudzi said in over 20 years in the service, he’d “never come across something like this.”