By Alexander Dziadosz
CAIRO (Reuters) - The Cairo hospital is full. Men are crammed two, three, four to a room. Their clothes are soaked with blood.
Their story starts the same way. It was dawn, they were praying. Then someone shouted, and they found themselves under fire by the military from all directions.
"They shot us with teargas, birdshot, rubber bullets - everything. Then they used live bullets," said Abdelaziz Abdel Shakua, a bearded 30-year-old who was wounded in his right leg.
He came from outside Cairo, like many people protesting against what they say was a military coup against the democratically elected President Mohamed Mursi.
With thousands of others, he says he went to camp peacefully outside the Republican Guard barracks where Mursi is being held.
The attack by the army, he says, took the protesters by surprise.
His is one of two opposing narratives of the violence that left more than 50 people dead, the deadliest episode since Mursi's overthrow on Wednesday and a sign of the widening rifts in the Arab world's most populous state.
The military disputes protesters' version of events. It has said a "terrorist group" tried to storm the Republican Guard compound and one army officer was killed and 40 wounded.
Soldiers returned fire when they were attacked by armed assailants, a military source said.
Another protester, Saber El-Sabaee says dawn prayers were abruptly cut short.
"First they started shooting teargas, and then guns above our heads. People started to fall back. Soldiers began shooting live bullets," he says, adding that armored vehicles emerged from the barracks escorting troops through the streets.
El-Sabaee felt something hit his head. Then he felt blood. He put his prayer mat to his head to try and staunch the flow. There was too much. His striped buttoned-down shirt is soaked through.
The army has also denied there was a coup, and said it was enforcing the will of the people after millions turned out on June 30 to demand Mursi's resignation.
Doctors and nurses move frantically through the hallways of the General Authority for Health Insurance hospital in Nasr City, which is less than a kilometer from the main pro-Mursi rallies in northeastern Cairo.
Some shout to clear the way. Stretchers are wheeled through. Men slouch in the hallways, some with their heads in their hands. Handwritten lists of names of the wounded are posted in hospital corridors. No one yet knows how many wounded or dead have arrived.
Mustafa Shalaby, a young doctor at the hospital, says he counted at least 45 dead and more than 400 wounded. About a tenth of those hurt were in an "unstable condition". Most were hit with live ammunition, he says.
When other hospital officials are asked how many casualties there are, they yell out in frustration. "No one knows," a medic shouts. "You won't find a single room empty." Another medical official waves journalists away.
Crude handguns have been used by protesters in recent violence - against soldiers and rival demonstrators.
Some of the wounded say they are trying to comprehend why the army, an institution some say they respected, would open fire. "I had full trust in the army," says Mahmoud Abdel Qader, 25, a teacher.
He wears a blue sweater, khaki shorts and rubber sandals. He was hit in the back with a bullet, he says. The stretcher-style bed he lies on is soaked in blood.
Abdel Qader blames army officers who wanted to preserve their privileges rather than rank-and-file conscripts, normal Egyptians like him.
He says foreign and domestic powers were scared that if Egypt went down the path of political Islam, the rest of the region would follow.
"This is about Islam, not more, not less."
(Writing by Alexander Dziadosz, editing by Mike Collett-White and Janet McBride)