Some news agencies reported that the gunfire erupted as police tried to force their way into the Al-Fath Mosque. Hundreds of people inside have been refusing to leave for fear of being attacked by crowds of "thugs" mingling with security forces outside.
The AFP news agency said police and military forces fired heavy bursts at the building after they were shot at from inside the mosque and from its minarets, a claim denied by protesters inside the mosque.
They pointed out that there was no access to the top of the minarets from inside the mosque and that an insider could not have taken up positions there to fire at security forces outside.
AFP reported that police managed to drag several men out of the building in the confusion. Those men were then confronted with angry neighborhood residents who attacked them with sticks and iron bars.
One man, Waleed Attar, was among a group who managed to escape the building as gunfire erupted. He told Al Jazeera: "We didn't know where the bullets were coming from."
He said they managed to flee and avoid "thugs" waiting outside. "We found our way between vehicles before the thugs could trap us, we ran for fear of being shot. Many of those trapped were being assaulted by thugs. They said we would all be slaughtered."
Earlier, speaking to Al Jazeera by phone from inside, protester Omaima Halawa said there was shooting inside and outside the building. Cracks of automatic gunfire and screaming could be heard in the background as she spoke. Halawa said there were about 700 people inside, including women and children.
A witness to the shooting, Abdel Kouddos, told Al Jazeera: "There were scenes of heavy gunfire. Police and security forces began firing at the minarets. Shortly after that there was fire from inside the mosque. It was unclear who was doing the shooting."
Anti-coup protesters found refuge in the mosque late on Friday after a "day of rage" protests called by opponents of the country's military-led leadership turned to bloodshed.
Reports said at least 95 people were killed in Ramses Square when security forces fired on marchers - the worst violence witnessed on Friday. The Al-Fath Mosque was turned into both a morgue and a field hospital for those injured.
At least 173 people were killed and 1,330 others were injured nationwide on Friday, according to a government spokesman.
Friday's marches were organized in response to police action on Wednesday to remove protesters from sit-ins calling for the return of the deposed president, Mohamed Morsi, and the end of military rule.
An estimated 600 people were killed in the operation.
Mostafa Hegazy, a political adviser for the interim presidency, said in a statement on Saturday that authorities were "facing a war launched by extremist forces" which was "escalating every day to a terrorist war".
He said that all indicators showed that what was happening "was not political disagreement, but a wave of violence and terrorism".
The Brotherhood denounced Friday’s killings, saying the coup leaders had "lost their minds" and were devoid of any ethics and moral values.
It added that the military coup against Morsi has backfired and it was time for the leaders to accept this fact.
The Brotherhood has meanwhile called for a week of daily protests in defiance of the government's state of emergency and curfew.
Amnesty International has denounced the interim Egyptian authorities’ response to the demonstrations as “grossly disproportionate.”
On July 3, army chief Abdel Fattah al-Sisi announced that Morsi, a leading former member of the Brotherhood, was no longer in office and declared that the head of the Supreme Constitutional Court, Adly Mahmoud Mansour, had been appointed as the new interim president of Egypt. The army also suspended the constitution.
Army officials said Morsi, who took office in June 2012, was being held “preventively” by the military.
On July 5, Brotherhood supreme leader Mohammed Badie said the coup against Morsi was illegal and millions would remain on the street until he is reinstated as president.
Badie vowed to "complete the revolution" that toppled the Western-backed regime of former Egyptian dictator Hosni Mubarak in 2011.
The Egyptians launched a revolution against the pro-Israeli regime on January 25, 2011, which eventually brought an end to the 30-year dictatorship of Mubarak on February 11, 2011.
MNA
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