Egypt's interim government has announced a month-long state of emergency in response to the violence that has raged across parts of the country.
The army has been ordered to help restore order after clashes killed scores of people in Cairo and elsewhere. The violence erupted when government troops cleared pro-Mohamed Morsi supporters from camps in the capital.
Troops have been instructed to take all necessary steps to preserve security, a televised announcement said.
Troops backed by armoured bulldozers and police helicopters moved in to clear pro-Morsi protest camps in Rabaa al-Adawiya and Nahda Square in Cairo and opened fire on demonstrators.
A clear-up operation was under way at the camps. Morsi supporters were reportedly chased into Cairo University and the city zoo. Fires started by aronists have been reported in several parts of the city and fighting has broken out in other main urban centres.
At least five people died in the city Suez after Morsi supporters tried to breach government buildings and three churches were attacked in central Egypt. A large mob gathered in protest outside the governor's office in Aswan and clashes have taken place in Alexandria, Beheira, Menya and Assiut.
Estimates of the overall death toll vary wildly. Egypt's health ministry said that 95 people had been killed but the Muslim Brotherhood's Freedom and Justice Party put the number of fatalities at 2,000.
Among those killed in the violence were Asmaa el-Beltagy, the 17-year-old daughter of the Brotherhood's senior leader Mohammed el-Beltagy, and Sky cameraman Michael Deane, who was covering the clashes at the Rabaa protest camp.
UN Secretary General Ban Ki-moon's spokesman Martin Nesirky urged negotiations to end the violence.
All Egyptians [must] concentrate their efforts on promoting genuinely inclusive reconciliation," he said.