However, the injured included six policemen, the official added.
With a roar that echoed across much of the city, the explosion shattered the facade of the National Security Agency building and damaged many nearby structures. Its homegrown status likely makes it more attentive to local sentiment. In the east of the country, in the Sinai Peninsula, a violent insurgency is being fought between government forces and the Province of Sinai. Of those hurt, 11 were police and soldiers.
Six policemen were among those wounded in the explosion but officials said none of the injuries were life-threatening.
For blocks around the blast site in the popular residential neighbourhood, glass from blown-out windows could be seen on the street.
The blast was so huge a crater was left at the scene and a burned-out auto was thronw into the air.
In May, Egypt executed six men it said belonged to the cell in Arab Sharkas.
According to their lawyer and relatives, three of the men could not have participated in the attack for which they were on trial and were already in custody when it was carried out.
The law, which Sisi ratified on Sunday, also threatens journalists who report non-official casualty statistics for attacks on security forces with fines of between 200,000 and 500,000 Egyptian pounds ($25,500- $63,800).
But the foreign ministry hit back at these criticisms, insisting that other countries should “respect the independence of the (Egyptian) judiciary”.
“We were here painting the office, and then it went off. It was like an quake, it blew the doors off and smashed all the windows in”, he said. “It was like an quake”, said Hady Gad, a resident living behind the building.
Egypt has been roiled by violence and turmoil since the military unseated democratically-elected President Mohamed Morsi in 2013. Hundreds have been killed and thousands jailed. The new law “brings in all sort of new layers of potential repression: it allows courts to ban journalists from practicing their profession and has a very vague definition for facilitating terrorism”, Houry suggested.