Egyptian security forces, backed by armored cars and bulldozers, swept in on Wednesday to clear two sit-in camps of supporters of the country's ousted president Mohammed Morsi, showering protesters with tear gas as the sound of gunfire rang out at both sites.
At least three members of the security forces were confirmed to have died in the morning's crackdown in Cairo, while the health ministry said nine protesters were killed and over 80 were injured.
The political arm of Morsi's Muslim Brotherhood claimed that more than 500 protesters were killed and some 9,000 wounded in the two camps on opposite ends of the city, but there was no official confirmation of the Islamist group's figures. There was nothing in the footage provided by the Associated Press or local TV networks that suggests such a high death toll.
Mohammed el-Beltagy, a senior Brotherhood leader, put the death toll at more than 300 and called on the police and army troops to mutiny against their commanders and on Egyptians to take to the streets to show their disapproval of Wednesday's raids on the sit-ins.
"Oh, Egyptian people, your brothers are in the square ... Are you going to remain silent until the genocide is completed?" said el-Beltagy, who is wanted by authorities to answer allegations of inciting violence.
The smaller of the two camps was cleared of protesters by late morning, with most of them taking refuge in the nearby Orman botanical gardens, inside the sprawling campus of Cairo University and the zoo.
An AP reporter at the scene said security forces were chasing the protesters in the zoo.
Security forces have stormed the larger camp in the eastern Cairo district of Nasr City and were closing in on a mosque that has served as the epicenter of vigil. Several leaders of Morsi's Brotherhood are thought to have been staying inside the mosque.
Wednesday's attacks on the two pro-Morsi camps are the latest chapter in the turmoil that has roiled Egypt since the 2011 ouster of autocrat Hosni Mubarak and are likely to deepen the nation's division between the camp of Islamists led by the Muslim Brotherhood on one side, and secularists, liberals, moderate Muslims and minority Christians on the other.
One of the security officials said a total of 200 protesters were arrested from both sites on Wednesday.
The pro-Morsi Anti-Coup alliance claimed that security forces used live ammunition, but the interior ministry, which is in charge of the police, said its forces only used tear gas and that they came under fire from the camp.
"The world cannot sit back and watch while innocent men, women and children are being indiscriminately slaughtered. The world must stand up to the military junta's crime before it is too late," said a statement by the Brotherhood's media office in London emailed to the AP in Cairo.
Islam Tawfiq, a Brotherhood member at the Nasr city sit-in said the camp's medical center was filled with dead bodies and that the injured included children.
"No one can leave and those who do are either arrested or beaten up," he told the AP.
The interior ministry statement also warned that forces would deal firmly with protesters who were acting "irresponsibly," suggesting that it would respond in kind if its men are fired upon. It said it would guarantee safe passage to all who want to leave the Nasr City site but would arrest those wanted for questioning by prosecutors.
The security officials said train services between the north and south of the country have been suspended in a bid to prevent supporters of the ousted Morsi from travelling to Cairo to reinforce fellow Islamists. Clashes erupted on a major road in Cairo's upscale Mohandiseen district when poro-Morsi protesters opened fire on passing cars and pedestrians. Police used tear gas top chase them away.
The officials spoke on condition of anonymity as they were not authorized to talk to media.
Police also fired tear gas elsewhere in Cairo to disperse Morsi supporters who wanted to join the Nasr City camp after it came under attack. State TV also reported that a police captain had been abducted by pro-Morsi protesters near the Nasr City camp.
In the city of Bani Suef south of Cairo, protesters set three police cars on fire. Farther south in the city of Assiut, a stronghold of Islamists, police used tear gas to disperse thousands of Morsi supporters gathered in the city center.
Army troops did not take part in the two operations, but provided security at the locations. Police and army helicopters hovered over both sites as plumes of smoke rose over the city skyline hours after the police launched the simultaneous actions shortly after 7am (0500 GMT).
Regional television networks were showing images of collapsed tents and burning tires at both sites, with ambulances on standby. They were also showing protesters being arrested and led away by black-clad policemen.
At one point, some dozen protesters, mostly men with beards in the traditional Islamist garb, were seen cuffed and sitting on a sidewalk under guard outside the Cairo University campus. The private ONTV network showed firearms and rounds of ammunition seized from protesters there.
At least 250 people have died in clashes in Egypt following Morsi's ouster in a military coup on July 3 that followed days of mass protests by millions of Egyptians calling for his removal.
Supporters of the Islamist president want him reinstated and are boycotting the military-sponsored political process which includes amending the Islamist-backed constitution adopted last year and holding parliamentary and presidential elections early next year.
Morsi, Egypt's first freely elected president, had just completed one year in office when he was toppled. He has been held at an undisclosed location since July 3, but was visited by the European Union's foreign policy chief Catherine Ashton and a team of African statesmen. Ashton reported that he was well and had access to television and newspapers.
Several bids by the United States, the EU and Gulf Arab states to reconcile the two sides in Egypt in an inclusive political process have failed, with the Brotherhood insisting that Morsi must first be freed along with several of the group's leaders who have been detained in connection with incitement of violence.
The trial of the Brotherhood's leader, Mohammed Badie, and his powerful deputy Khairat el-Shater on charges of conspiring to kill protesters is due to start later this month. Badie is on the run, but el-Shater is in detention. Four others are standing trial with them on the same charges.