CAIRO (REUTERS) - A call by Egyptian army chief Abdel Fattah al-Sisi for mass protests on Friday against "violence and terrorism" amounts to a threat against the Muslim Brotherhood, a senior member of the group said.

"Your threat will not stop the millions from continuing to gather," Mr Essam El-Erian wrote on his Facebook page on Wednesday, calling Gen Sisi "a coup leader who kills women, children and those at prayer".

Around 100 people have been killed since the army deposed Islamist President Mohamed Mursi on July 3, most of them supporters of his Muslim Brotherhood who died in street clashes with the military and Mr Mursi's opponents.