More than 3,700 have been injured, according to the Health Ministry.
Mohamad Fathallah, the Health Ministry spokesman, told the official Al Ahram Web site that the toll so far stood at 525 with 3,717 injured. He said the biggest concentration of killings, numbering 202, had been in the larger of the two protest camps in Nasr City suburb, with 87 recorded in the smaller Nahda Square camp near Cairo University. A further 29 deaths were reported from the Helwan area on the outskirts of Cairo with 207 from other areas around the country.
“We will always be nonviolent and peaceful. We remain strong, defiant and resolved,” Gehad El-Haddad, a spokesman for the Muslim Brotherhood, wrote in a message on Twitter. “We will push forward until we bring down this military coup,” he said, referring to the ouster of Mr. Morsi six weeks ago.
The mass killing of Islamist demonstrators is the third since the overthrow, but possibly the most ferocious.