Supporters of ousted Egyptian President Mohammed Morsi chant slogans during rally in Nasr City, Cairo, Thursday, July 4, 2013. Morsi was removed from office by the nation's military.
CAIRO (CBS/AP) -- Egyptian security forces, backed by armored cars and bulldozers, moved on Wednesday to clear two sit-in protests by supporters of the country's ousted president, Mohammed Morsi, showering protesters with tear gas as the sound of gunfire rang out at both sites, state television and security officials said.
The Muslim Brotherhood, the well-organized Islamist group which propelled Morsi into office and continues to demand his reinstatement, said in a statement that at least 60 people were killed and dozens injured in the attack on the larger of the two protest camps, at the Rabaah al-Adawiya mosque in the eastern Cairo district of Nasr City.
The state news agency said only that two members of the security forces were killed by gunfire.
CBS News' Alex Ortiz said police and army personnel had blocked every road into the area around the Rabaah camp, and pro-Morsi demonstrators were clashing with police outside the cordoned-off area, too. He said huge plumes of black smoke were rising over the camp and continuing automatic gunfire could be heard coming from the site.
Prominent Muslim Brotherhood leader Mohammed al-Biltagi told the Al Jazeera television network that as many as 300 people had been killed in the crackdown on the Rabaah camp, calling it a "crime against humanity."
"I urge all the Egyptians to take to the streets and protest against the violent break-up of the sit-ins," said al-Biltagi. "By Allah, I have seen toddlers being killed in front of their mothers."
There was no official word on casualties among the protesters in either camp. State television said only that two security force members were killed.
Sam Kiley, a veteran war correspondent for CBS News partner network Sky News, reported from the Rabaah camp that there were scenes of "extreme horror" in a field clinic set up near the mosque. He said he had seen many people lying on the ground with severe wounds to head and chest, clearly from live ammunition.
"Live fire seems to be principle method being used to clear the area," said Kiley, adding that he had seen many dead, but that numbers being reported as death tolls were unlikely reliable and the "numbers are escalating constantly."
The Interior Ministry, which is in charge of police, warned in a statement that the forces would deal firmly with protesters acting "irresponsibly" and said it would guarantee safe passage to those who want to leave the sites.
A former government aide who's been attending the Nasr City protest every day told CBS News that security forces took out a stolen State TV satellite truck first with live ammunition, then began firing volleys of tear gas into the camp.
The simultaneous actions by the Egyptian forces -- at the pro-Morsi encampment in Nasr City and at the site outside the main campus of Cairo University on the other side of the capital -- began around 7 a.m. local time. Helicopters hovered over the two sites.
Regional television networks were showing images of collapsed tents and burning tires at both sites, with ambulances on standby at the scene. They were also showing protesters being arrested and led away by the troops.
There were reports that the clashes had spread to other Egyptian cities, suggesting police and pro-Morsi protesters were facing off in Giza, Alexandria, Assiut and al-Minya.
At least 250 people have died in clashes in Egypt following Morsi's ouster in a military coup that followed days of mass protests by millions of Egyptians calling for his removal.