Police authorities in Cairo, Giza, and Qalyubiya governorates received several reports on Wednesday around 11:30 am that citizens heard massive explosions, a security source said.
While a security source in the Cairo district of Helwan said the sounds might be attributed to quarrying work, Cairo Security Chief Mohsen Morad told state-run TV that an airplane breaking the sound barrier had produced the noise.
The security source added that police forces were put on alert and some were deployed to the areas where explosions were heard to determine the cause of the noise.
Translated from the Arabic Edition
