There were tense scenes at the pro-Morsi sit-in in Cairo's Nasr City on Monday afternoon as the army increased its security presence and the injured continued to be treated in makeshift field hospitals near Rabaa Al-Adawiya Mosque.
Clashes between protesters and security forces at the nearby Republican Guard headquarters left at least 51 dead and hundreds injured shortly after dawn on Monday.
Dozens of armoured personnel carriers gathered on Saleh Salem Road, which runs parallel to the headquarters.
Supporters of deposed president Mohamed Morsi had extended their encampment from Rabaa Al-Adawiya Mosque to block this main road on Sunday, putting up signs reading "Egypt is closed until the return of President Morsi."
Meanwhile, at the Nasr Road entrance to the protest, dozens of military officers, some in balaclavas, were stationed by the wayside after firing volleys of teargas and shooting automatic weapons into the air in a bid to prevent more people from joining the demonstration.
Back at the sit-in, doctors in the makeshift field hospital said they were overwhelmed by the number of injured from the clashes.
"At first, around dawn, we had live ammunition wounds coming in; one guy was shot in the neck. We had over 40 dead, including a ten-month-old child and a 65-year-old woman," said Dr Hassan Ahmed, an emergency medic at Cairo's Qasr Al-Aini hospital, who had been manning the field hospital at the sit-in.
"We had many birdshot wounds to the face, seven to the eyes. Ambulances were getting in but only a handful, we had hundreds who needed proper medical assistance, so we had to deal with the patients here and make priorities."
Dr Said Khalifa, another doctor attending the wounded, said he saw birdshot and live ammunition wounds, trauma patients and people suffering from teargas inhalation.
"People have been coming in with severe burns to their legs as well, I'm not sure what from," Dr Khalifa added. "The first case I saw had died instantly after bullets entered his back and came out though the front. The other cases were superficial wounds that passed through the skin."
As the doctors were talking to Ahram Online, another injured man, in his fifties, was bought in with a gunshot wound to his back, probably caused by rifle fire, medics said.
Protesters holding bloody flags moved around the sit-in piecing together what had happened while the names of those killed were being read out on the demonstration's main stage.
Eyewitnesses insisted the security forces had attacked protesters when they were praying at dawn.
"Our backs were to the military forces, the forces of the Republican Guards. We heard some people shouting from the eastern area that people were coming," said eyewitness Rafaat Mustafa, a 50-year-old company director from Cairo.
"They started firing teargas and bullets. There were many women and children. The women started crying, the children couldn't breathe, five of them died," Mostafa said.
Mustafa added they tried to evacuate the women but it was impossible amid the chaos.
"We felt we were in a battle. People were using nothing but their hands; they faced the soldiers with bare hands. They are our friends, our people, our sons, our brothers."
Magdy Ahmed Abu-Zeyed, 36, from Fayoum, said soldiers attacked those who took cover in surrounding buildings. "They arrested whoever was left and took them to prison."
Army denies it attacked
None of these stories can be verified and there are conflicting versions of events.
Military spokesman Ahmed Aly said in a press conference on Monday afternoon that army and police forces protecting the Republican Guard headquarters were attacked on Monday by armed groups.
According to Aly, pro-Morsi protesters, who have been gathering outside the Republican Guard headquarters for days, used live ammunition and bird shots against security personnel.
He added that at the time of the attack, another group was shooting from atop a building on Al-Tayaran street, where the military facility is located.
"A colleague is in Maadi hospital undergoing a four-hour surgery; he was shot with live ammunition in the head, which caused his skull to fracture," said Aly.
Aly said that the officer's injury proves that there was firing from building rooftops.
Moreover, Egypt's Health Insurance Authority head Abdel-Rahman El-Sakka said on Monday afternoon that he had seen no evidence that women and children were among the dead and injured.
Fearing further violence, supporters of the deposed president have reinforced the barricades surrounding the sit-in.
"As you can see the helicopters keep monitoring the people here," said Abdullah Ali, an 18-year-old student, pointing to military helicopters circling overhead. "We're not scared of death. We will stay here to defend our freedom."
Prosecutors said they had found bullets, birdshot and Molotov cocktails in the vicinity of the clashes near the Republican Guard headquarters.
A delegation of prosecutors visited Zenhom morgue, where some of the dead were taken, while another interviewed victims in local hospitals.
Constitution Party leader Mohamed ElBaradei has called for an independent investigation into clashes.
“Violence begets violence and should be strongly condemned,” ElBaradei said via Twitter. “Independent investigation a must. Peaceful transition is only way.”
Shortly after the clashes, Strong Egypt Party leader Abdel-Moneim Abul-Fotouh, a critic of former President Morsi, called on interim president Adly Mansour to step down.
Abul-Fotouh, who resigned from the Muslim Brotherhood shortly after the 2011 uprising, told Al Jazeera that the incident was "a horrible crime against humanity and all Egyptians."
Also on Monday, the Salafist Nour Party, which had initially backed the ouster of President Morsi, announced that it "will withdraw from the political process" in response to the incident.
"We wanted to avoid bloodshed, but now blood has been spilled. So now we want to announce that we will end all negotiations with the new authorities," Nour added.