Security forces in Sharqia governorate declared a state of maximum alert as some terrorist groups called for violent protests and riots on Sunday, the fourth anniversary of the 25 January revolution.
More fixed and mobile checkpoints were set up in the governorate's squares and main streets, Security Chief Sameh el Kelany said.
Extra precautions were put in place on Saturday to prevent violence, he added.
Counter terrorism units were posted around police facilities, churches, banks and jails, he pointed out.