Shortly after dawn prayers on 8 July 2013, security forces killed at least 51 protesters and injured 435 more in front of the Republican Guard headquarters on Salah Salem Road.
The sit-in was to protest the military ouster of former president Mohamed Morsi on 3 July 2013.
While the event was one of the more violent ones since the days of ousted president Hosni Mubarak, it would pave the way for further killings.
According to Amnesty International and Human Rights Watch (HRW) reports conducted at the time, security forces used “excessive” and “intentional lethal force” whilst shooting at protestors.
However, in a press conference, the police and military forces denied excessive force and alleged that the attack had been prompted by protestors.
A 43-year-old Muslim Brotherhood supporter, Mohsen Sudan, told HRW: “[At dawn] we were finishing up our prayers. We heard the sound of gunshots and the imam rushed the end of the prayer. Then there was the sound of shooting from the left side [from the direction of Mostafa Mosque]. After 15, maybe 20 minutes, people started to fall. I ran back, away from the Republican Guard headquarters.”
“There were snipers on one of the military buildings. I was in the middle of the road [perpendicular to Salah Salem and leading to the Republican Guard headquarters] and I saw two youth filming from their balcony. The snipers [across the road] shot at them. They continued shooting until 10.30am,” Sudan said.
Following the violent incident, military and security forces went on to violently disperse two sit-ins in Rabaa Al-Adaweya and Al-Nahda Squares on 14 August 2013, killing at least 1,000 protestors, according to HRW counts.