Menoufia police on Saturday arrested three members of the terrorist Muslim Brotherhood (MB) group after dispersing a protest at the province's el Sadat City.
No clashes or injuries were reported, said a security source.
Dozens of the group members staged a rally to protest the court ruling that found former president Hosni Mubarak, his sons and other regime figures not guilty.
The participants chanted anti-army and police slogans before the police forces arrived at scene, arresting three rioters in possession of fireworks.