More than 100 people were killed and 1,500 injured during clashes at a sit-in by supporters of ousted Egyptian president Mohamed Morsi in the Rabaa Al Adawiya mosque area, in Nasr City, Cairo.

According to the Daily News Egypt, the Public Prosecution have started investigations into what happened late that Friday [July 27] night.

Egyptian blogger Mosa'ab Elshamy was at the scene and shares what he saw in the following tweets:

It was unclear to me who ‘started’ the attack. But the clashes were at the begining of Tayaran street, 100 metres away from the sit-in. (2)

— Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

It was unclear to me who ‘started’ the attack. But the clashes were at the begining of Tayaran street, 100 metres away from the sit-in. (2) — Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

There was a non-stop sound of gunshots. The dark meant it was suicide to stay there. So I went to Rabaa's makeshift hospital. (3) — Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

Most of the cases I saw where people shot in the leg and chest with live bullets. Hours later, I counted 24 dead bodies at the morgue. (4) — Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

I saw at least 3 men who were shot in the head. Some claimed snipers were on October bridge, which would make sense. (5)

— Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

After dawn I went to the frontlines. Next to the police there were armed civilians who seemed to be a mix of residents and thugs. (6) — Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

I was on Morsi-supporters’ side of the clashes for about 5 hours and honestly saw no arms with them. (7)

— Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

Pro-Morsis mostly just took cover, threw rocks, fireworks and gas canisters back until they got shot at & carried away. Then repeat. (8) — Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

I didn't see any military involvement. Except when soldiers at Manasa shot in the air and caused both sides to back away for a while. (9)

— Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

My conclusion is that this was, undoubtedly, a horrific assault by MOI + ‘civilians’ with tear gas, rubber bullets and live fire. (10) — Mosa'ab Elshamy (@mosaaberizing) July 27, 2013

Rabaa … After the clashes. Photograph by Mosa'ab Elshamy. Used with permission.

On flickr, he shares these photographs from the tragedy.