An Egyptian security official says an explosion has damaged the building housing the Italian Consulate in downtown Cairo.

The blast early Saturday morning 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.

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.