TEHRAN — A historic high-rise building in the heart of Iran’s capital caught fire and later collapsed Thursday, killing at least 30 firefighters and leaving their stunned colleagues and bystanders weeping in the streets. The disaster at the 17-story Plasco building, inadvertently shown live on state television, came after authorities said they repeatedly warned tenants about blocking stairwells with fabric from cramped garment workshops on its upper floors. While it was not clear how many people were in the steel-and-concrete building, witnesses said many had slipped through a police cordon while the fire burned to go back inside for their belongings. “They asked us ...