The latest clashes were spurred by el-Sissis call last week for Egyptians to rally in support of the military Friday so that it would have a mandate to combat violence and terrorism, which government officials recently have obliquely equated with Morsi supporters.
Millions heeded el-Sissis call in celebratory rallies, carrying el-Sissis picture. Late Friday, the military issued a statement, thanking demonstrators for their support.
The violence came just a few hours later, in the middle of the night and continuing for hours, when many here were already expecting the military to attempt to clear pro-Morsi demonstrators from the sit-in, which theyve been holding since June 28.
Just how the violence began is uncertain. The official version from the minister of the Interior, Mohammed Ibrahim, who oversees the countrys security services, said pro-Morsi protesters were headed toward pro military supporters and that the military simply wanted to stop them from reaching the 6th of October bridge, a key thoroughfare near Cairos iconic Tahrir Square. The official account said security forces fired tear gas to deter the pro-Morsi crowd and that 14 policemen were injured when the demonstrators retaliated.
Morsi supporters rejected that account.
"First of all, the march was heading to Abassya and there were no pro-military protesters there," said Adham Hassanien, 31, a journalist who works in a media center set up by Morsi supporters, referring to an area in Cairo where the Ministry of Defense is located.
He also discounted that Morsi supporters had attacked the security forces in any way, noting that the Rabaa protest had been going on for nearly a month. "Why would we attack them now? We are the ones who are losing people," he said.
To be sure, many Morsi supporters were armed. And in the past month, on a stage at the site, sheikhs have repeatedly told Morsi supporters that to die for his reinstatement is an honorable, Islamic form of martyrdom.
But the number of deaths and the severity of the wounds suggested that if there had been any resistance on the part of the Morsi supporters, it was easily overwhelmed.
What the repercussions will be of the violence are unclear. Security forces killed more than 50 pro-Morsi demonstrators outside the headquarters of the countrys elite Republican Guard July 8 with barely an outcry from either Egyptians or the international community. The government said then that protesters had tried to storm the Republican Guard headquarters, where some believe Morsi was being held, but witnesses in two apartment buildings overlooking the scene told McClatchy they believed the government fired first.
Egypts general-prosecutor, Hisham Barakat, said he had ordered an investigation into Saturdays events, and the powerful al Azhar Mosque called for the criminal responsible to be punished. But with the majority here clearly supporting the crackdown on the Brotherhood, as the turnout on Friday showed, an aggressive probe seemed unlikely.
State television, which had trumpeted Fridays demonstrations and cancelled its usual fare of soap operas to encourage the turnout, made little mention of Saturdays violence and resumed its regular programming.
At a news conference Saturday, Interior Minister Ibrahim showed little regret, saying Morsi supporters would be dealt with, God willing.
Ibrahim said he planned to reinstate departments to combat extremism and monitor political and religious activities that had been eliminated during Morsis time in office. Those offices had been used primarily to target the Brotherhood.
Since Morsis July 3 ouster by the military, at least 200 people and troops have been killed, largely Morsi supporters and Islamists who reject an Egypt again governed by the military. The latest clashes likely bolster the Brotherhoods case that the military was taking Egypt back to a totalitarian state, but many Egyptians are so relieved Morsi is no longer in power, they consider that the better option.
Morsi has been held in an undisclosed location since el-Sissi announced that he was no longer president. On Friday, a judge announced that the deposed president would be held for 15 more days as officials investigate him for murder and espionage for allegedly conspiring with the Palestinian group Hamas to orchestrate his 2011 prison break, the first time the government had offered a legal justification for his detention.
On Saturday, Ibrahim said it was likely Morsi would be moved to the same prison as former Egyptian President Hosni Mubarak, who resigned two years ago after massive public demonstrations demanded he step down, and the military signaled he too had lost the publics support.
Except for Morsis 368 days as president, a current or former military officer has ruled Egypt for the past six decades.