Egyptian troops have opened fire on supporters of ousted President Mohammed Morsi marching in Cairo, killing three people and wounding dozens more.
The shooting came as crowds moved on the Republican Guard headquarters, where Mr Morsi is believed to be held.
Later the Muslim Brotherhood's leader told supporters that protests would continue until Mr Morsi was reinstated.
The army, which removed Mr Morsi on Wednesday after days of unrest, denied shooting live rounds at demonstrators.
However the BBC's Jeremy Bowen at the scene says he saw soldiers fire on the protesters on Friday.