A loud boom heard across Cairo was caused by a fast-flying jet, an official said Wednesday, after the sound stirred panic among many Egyptians.
The head of Cairo security forces, Mohsen Murad, said the bang occurred when a pilot broke the sound barrier, according to state television.
The explosive sound shook buildings in at least six different districts across the Egyptian capital on Wednesday morning.
However, a security source told the German Press Agency dpa that the sound was due to an explosion inside a quarry in southern Cairo.
Meanwhile, other sources said it was caused when a bridge collapsed near the southern neighbourhood of Maadi, leaving four workers dead.
The sound, and discrepancies between reports about its origin, caused a degree of panic throughout the city.