A fire broke out in a five-storey building in Istanbul's Arnavutköy district. The cause of the blaze has not yet been determined. Reports from the scene indicate that people were trapped inside the structure when the flames took hold. Firefighters arrived quickly and their efforts to douse the fire are still under way. Residents nearby watched as smoke poured from the building and crews worked the scene. No confirmed casualty or injury figures have been released at this point. Authorities are expected to provide an update once teams bring the situation under control.