Thousands of Morsi backers also showed their defiance by briefly setting up a third sit-in near the airport, but folded their tents and left about six hours later after organizers deemed the site to be insecure.
The military-backed interim government seeks to end a political stalemate that has paralyzed Egypt and deeply divided the country. Supporters of Morsi and his Muslim Brotherhood say they will not disperse until he is returned to power.
Deputy Secretary of State William Burns arrived in Cairo Friday to urge Egyptian leaders to avoid violence and help facilitate a political exit strategy to end the stalemate that has paralyzed Egypt and deeply divided the country.
An Egyptian Foreign Ministry official said Burns would meet with interim leadership officials and representatives from the Muslim Brotherhood and its allies Saturday.
Amr Darag, one of the Brotherhood negotiators who will meet with Burns, said that the group and its allies are looking for “confidence-building measures” in order for them to sit at the table with their rivals.
Such measures include releasing detained Brotherhood leaders, unfreezing the group’s assets, lifting the ban on its TV stations and ending violence against its protests. Darag said the group can’t order its protesters to go home because they are fighting for their rights and the reinstatement of Morsi as president.
It was unclear if Burns would see Morsi during his second visit to Cairo since the coup.
Meanwhile, Amnesty International reported cases of alleged killings and torture Friday at the hands of Morsi supporters inside the protest camps.
The report also cited accounts from survivors that Morsi backers also abducted and tortured their political opponents with beatings and electric shocks at or near the protest sites.
The Interior Ministry last weekend had said 11 bodies were found near one of the protest sites, with some showing signs of torture, apparently by members of the sit-ins who believed the victims were spies.
Near the Rabaah protest camp Friday, people armed with sticks and makeshift body armor stood guard behind walls of sandbags, tires and bricks.
The new unrest came as state-controlled TV reported that security forces will establish a cordon within 48 hours around the two main protest sites in Cairo where thousands have been camped out since before Morsi was ousted by the military on July 3.
The government offered protection and “safe passage” to those willing to leave the two main camps — a large one outside the Rabaah al-Adawiya Mosque in eastern Cairo and a smaller one near Cairo University’s main campus in Giza. The leadership had earlier given orders to police to end what it described as “threat to national security” and sources of “citizens’ terrorism.”
Authorities will let people leave without checking their identities or arresting them, but they will not allow anyone into the protest camps, the report said. It did not elaborate on the next steps, but the government earlier said it will use water cannons and tear gas in dispersing the crowds.
The security cordon around the protest camps raises the possibility of new violence, which has killed more than 130 Morsi supporters and injured hundreds since the military coup. The ouster followed mass demonstrations calling for Morsi to step down after a year in office, saying his policies had failed and he had put power in the hands of his Islamist group.