The blast caused extensive damage to the building's exterior and ruptured underground water pipes, flooding the area. The official said
the exact cause of the explosion was still unclear, as was the extent of any casualties, AP reported.
The explosion struck one of the busiest intersections in Cairo, a major artery that connects Ramsis Square to the heart of downtown Cairo. Even before 7 a.m. on a weekend in the middle of the Islamic fasting month of Ramadan, the area around the blast would have been crowded with cars, pedestrians and mini-buses.