Atef Khedr, head of the local criminal investigations unit, told the Arabic language newspaper al-Ahram a car bomb exploded next to the intelligence building, partially destroying it.
Ahmed Ali, the army's spokesman, wrote on his Facebook page that four soldiers were injured in the blast, Ahram Online said.
It is the third bombing in Egypt in the past week. Last Tuesday, 16 people were killed and dozens injured when two explosions rocked security headquarters in Mansoura. Five people were injured Thursday when bomb exploded next to a bus in Cairo's Nasr City. A second bomb was defused in that attack.
In unrelated news, clashes erupted between security forces and supporters for ousted President Mohamed Morsi on the male campus of Cairo's al-Azhar University Sunday morning, Ahram Online said. Morsi supporters called for a boycott of exams taking place at the school. Security forces stormed the university to ensure the exams went on unhampered, the website said.
Since Morsi's ouster in July, Egypt has been plagued with widespread violence with fierce clashes between Morsi's supporters and opponents and security forces. The Egyptian military has also become the target of bomb attacks.
Last week, the Egyptian government officially labeled Morsi's Muslim Brotherhood a terror organization.