Egypt's public prosecutor, Hisham Barakat, was killed last month by a car bomb attack in the city.
Three people were also killed in a car bomb that hit a police station in June.
Egyptian security forces have been battling Islamic militants, but the fighting has been mostly confined to the Sinai Peninsula.
At least 600 Egyptian police and armed forces personnel have been killed in the last two years. Militants increased their attacks after Islamist President Mohammed Morsi was overthrown in July 2013.
In recent weeks, Egyptian President Abdul Fattah al-Sisi has promised to crack down further on Islamist militants.
Hundreds of Muslim Brotherhood members, including ousted President Mohammed Morsi, have been sentenced to death by Egypt's courts.