Seven security forces personnel and two civilians were injured in an explosion at a security checkpoint in Qalioubiya governorate on Tuesday afternoon, the health ministry has said.
All the injured were transported to local hospitals.
The bomb detonated in Mostorod near a mosque complex.
Unknown assailants on a motorbike threw a primitive bomb at the security checkpoint, the local security directorate confirmed.
Tens of bombs were reportedly defused by police on the January 2011 revolution's fourth anniversary on Sunday, including many targeting railways.
Violent clashes between security forces and pro-Morsi protesters left at least 23 dead and 50 injured nationwide on Sunday.
Since the ouster of Islamist president Mohamed Morsi, security checkpoints have been a target for militants across Egypt.