Supporters and opponents of deposed President Mohamed Mursi will stage mass demonstrations across the country on Sunday.
A new alliance that groups all of Egypt's Islamist movements called for a demonstration in Rabaa al-Adaweya, by Cairo University and the Republican Guard's headquarters "to support legitimacy".
Rabaa al-Adaweya protesters refuse to leave the square until the Islamist president returns.
Meanwhile, "Tamarod" (Rebel) and the National Salvation Front, Egypt's main opposition alliance, have both called for people to rally in Tahrir, by the residential palace and al-Qubba palace.
Egypt's army ousted Mursi on Wednesday after millions took to the streets to express their rejection for him and his Muslim Brotherhood.
Confrontations between opponents and supporters left at least 30 people dead on Friday.