At least 15 people were killed in a building collapse in Egypt's capital Cairo Tuesday, media reported.Rescuers were working to remove the rubble of the eight-storey building in the city's Matariya suburb, state-run MENA news agency quoted Mamdouh Abdel Kader of Cairo's General Directorate for Civil Protection as saying. He said that eight people were wounded in the collapse. Initial investigations found that the building's collapse was caused by unauthorised construction of several extra floors, according to an official at Cairo's civil protection authority, Xinhua reported citing Ahram online. Nearby buildings have been evacuated, the official added, noting that the civil authority had previously ordered the old building to be evacuated for its poor condition, but the inhabitants did not respond.Building collapses are common in Egypt, where unlicensed construction had spread not only in the rural areas but also in the capital's upscale suburbs due to lax governmental supervision and greed of developers.