Security forces intensified their presence at Abdel Moneim Riad Square on Friday morning and sealed off all entrances leading to Tahrir Square in Cairo, Akhbar Masr website of the state radio and television union reported.
This is the first time the square has been sealed in weeks.
The National Coalition for Supporting Legitimacy has called on Egyptians to rally in the streets starting Friday to demand putting an end to what it called the coup.
The Islamist coalition supports former President Mohamed Mursi and calls for his return to power.
The armed forces deployed their tanks on the streets leading to Tahrir and set up barbed wires to prevent passersby from accessing the square.
Mursi's supporters have been staging protests since his overthrow to demand his return to power.