Egypt's interim government has moved towards dismantling two pro-Mohammed Morsi sit-in camps, accusing protesters of "terrorism" and vowing to deal with them decisively.
The move is likely to escalate the confrontation after clashes which left 83 supporters of the ousted Islamist president dead.
Mr Morsi's Muslim Brotherhood denounced Saturday's bloodshed as evidence of the brutality of the military-backed regime.
But many accused the group's leaders of trying to capitalise on the loss of life to win sympathy after millions took to the streets in a show of support for the military chief who ousted Mr Morsi in a coup.
Gen Abdel-Fattah el-Sissi said he would take the popular support as a mandate to deal with violence and "potential terrorism" - a thinly veiled reference to a widely expected crackdown on Morsi supporters in the sit-in camps in Cairo and against radical Islamists in the Sinai peninsula who have been waging deadly attacks against security forces since Mr Morsi was ousted in a July 3 military coup.
The coup followed days of mass protests by millions of Egyptians demanding that Mr Morsi step down after a year in office as Egypt's first elected president. The month-long sit-ins have been the launchpad of street protests that often ended violently when Mr Morsi's supporters clashed with opponents or security forces.
Islamists led by the Brotherhood staunchly reject the new post-Morsi leadership and insist the only possible solution to the crisis is to reinstate him. Meanwhile, the interim leadership is pushing ahead with a fast-track transition plan to return to a democratically elected government by early next year.
The Brotherhood, accused by critics of trying to monopolise power during Mr Morsi's year in office, routinely claims its supporters are killed in cold blood by army troops, police or thugs sponsored by the interior ministry, which is in charge of police. However, witnesses and videos posted on social networking sites show that Mr Morsi's supporters consistently use rocks, firebombs and firearms against opponents, who behave similarly.
The Brotherhood's tactic is clearly designed to win sympathy at home and abroad by portraying itself as a victimised party pitted against an army and a police force armed to the teeth.
"We urge the United Nations, the international human community to come down and rescue the hundreds of thousands from the massacre by the live ammunition in the hands of the criminals," senior Brotherhood leader Mohammed el-Beltagi shouted from the stage at the larger of the two Cairo sit-ins.