Scores of inmates from the Mit Salsil prison in Daqahlia protested on Saturday, later announcing a hunger strike to protest ill-treatment by the guards.
Central Security forces surrounded the prison and denied entry to the families of the prisoners.
Security sources accused the Muslim Brotherhood inmates of instigating the riots.
The prisoners said they had filed several complaints with the Security Directorate and the prosecutor General, accusing the guards of physical and verbal abuse.
Daqahlia Investigation Department Director Saeed Emara said the prisoners refused to allow for the daily inspection procedures for contraband, weapons and mobile phones.
Security Directorate officials succeeded in convincing the prisoners that defying the rules would cause them legal complications, and said the situation is now under control.
Edited translation from Al-Masry Al-Youm
