Mohamed al-Beltagi, a leading figure of the Muslim Brotherhood and its Freedom and Justice Party, said more than 300 people had been killed in the forcible dispersal of two sit-ins staged by supporters of ousted President Mohamed Morsi.
"Bullets are raining down on our heads," al-Beltagi told supporters who remained inside the besieged protest site. "More than 300 people have been killed."
He appealed to the Egyptian people to take to the streets in a show of solidarity with slain pro-Morsi demonstrators.
In the early hours of Wednesday, security forces moved in to forcibly disperse two six-week-old sit-ins in Cairo and Giza staged by Morsi supporters.
According to medics and eyewitnesses, at least 163 people have been killed and thousands injured.
The Egyptian Ambulance Organization, however, has put the number of people killed in the two squares at ten.
The Interior Ministry said three policemen had been killed in the violence.
MB leader urges world to intervene to stop 'massacre' of Morsi supporters.
PHOTO CAPTION
Sit-ins staged by supporters of ousted President Morsi
AA