Egypt's state prosecutor has issued an arrest warrant for the leader of the Muslim Brotherhood, Mohamed Badie, and other senior figures in the movement.
They are accused of inciting violence near a military barracks in Cairo on Monday that left 51 people dead - most of them supporters of ousted president Mohammed Morsi.
Many Brotherhood members are already in detention and warrants are said to have been been issued for hundreds more.
The Brotherhood, to which Mr Morsi belongs, says his ousting by the military last Wednesday amounted to a coup.
