Traffic around the square flowed smoothly because of an increased number of police officers but the usual street vendors were not seen, the Egypt Independent reported.
Ambulances were positioned at the entrances to the square, the report said.
The largest of the anticipated demonstrations was expected after Friday prayers at al-Azhar Mosque, where Youssef al-Qaradawy, chairman of the International Association of Muslim Scholars, was expected to speak.
Cairo had a series of protests Thursday after news spread of the Israeli attacks, Ahram Online reported.
Hundreds of Egyptians from nationalist and liberal groups protested for several hours outside of the headquarters of the Arab League, demanding an end to the attacks.
Some protesters later marched on the offices of the Egyptian Foreign Ministry.