At least 10 were killed at a second but much smaller sit-in site in Nahda, near Cairo University, which officials successfully cleared by mid-afternoon.
Among those killed at Rabaa were at least two journalists, including Sky News cameraman Mick Deane, a 15-year veteran. And despite government assurances that journalists would be allowed to see inside the sit-in, several were arrested or threatened when they tried.
There were also conflicting reports that the daughter of Brotherhood supreme leader Khairat al-Shater and her husband were killed in Rabaa, as well as Freedom and Justice Party leader Mohamed El Beltagy's daughter Asmaa, 17. The new government already had arrested Shater; Beltagy was believed to be hiding in Rabaa.
Rabaa, where Morsi supporters have been sitting - and in some cases living - since June 28, remained a sit-in by mid-afternoon, despite the carnage. But it now appeared more like a battlefield than a protest site. Residents positioned their cars as barricades and pieces of concrete were removed from the sidewalk and broken up to be used as rocks. As protesters tried to go to the hospital, they huddled and ran to the building to dodge the gunfire, which never stopped from the first attack at 7 a.m.
Witnesses said that an hour earlier military and police vehicles began surrounding the several block site, which included numbered tents, bathrooms and kitchens for the thousands living there. Around 7 a.m., forces threw tear gas into the crowds, said Mohammed el Nagger, 64, a carpenter who has been at the site since June 28, two days before Morsis first anniversary in office. Residents started to run out of the tents, el Nagger said.
Once the people went out into the open, they started shooting, said el Nagger, who was struck in the ankle.
His son, Kamel, 35, described a horrific scene of people trying to help each other, his bandaged hand shaking as he recalled the incident.
In front of my eyes I saw someone shot. Another man went to help him and he was shot too. They were lying on top of each other, he said. We cannot even move the dead outside.
Morsi opponents charged that they were marginalized under the former president, the first democratically elected leader in Egypts history. Facing growing unpopularity and unprecedented protests, the military announced he was no longer president, replaced by interim leader Adly Mansour. Morsis ouster spurred his protesters to stay in the sit-in until he was reinstated. In an instant, Morsi supporters went from governing the country to be branded as terrorists by their usurpers and the majority of Egyptians who opposed them.
Efforts failed in the past month of negotiations, both by Egyptians and the international community. Neither side could agree on who would represent them, let only the major divisive issues of the day.
Now in power again, the military and its civilian named government blamed the Brotherhood for the violence Wednesday urging them to side with reason.
As the clashes erupted, the Ministry of Interior urged protesters to use one exit point. But waiting for them there were local residents who vowed to beat up those leaving. On a bridge looking over the police vehicles stationed nearby, a man ripped a Morsi poster in front of the police.
Ahmed Tayab, sheikh of al Azhar, a revered institution of Sunni thought, condemned the violence and said he was unaware the security forces planned to clear the area. Indeed, he was scheduled to lead negotiations between the Brotherhood and the government Wednesday even as he shared the stage with el-Sissi during the July 3 announcement.
At the field hospital, so many bodies came in so quickly, it was clear there was not room for them. Sha-heed! or Martyr protesters would yell as another dead man came by. Those who were lucky enough to escape the site sought treatment at a nearby mosque turned hospital. Some tried to take off their shoes at the doors in accordance with religious customs.
This no time to take off shoes! the imam yelled as blood soiled the mosque carpets. Every few minutes a man would be carried in, the women would scream and there were quiet murmurs of what the days events meant for Egypts future.
We can no longer be peaceful, a Morsi supporter said as he carried an injured friend into the morgue.
Video, images (some graphic) from Wednesday's attacks: