Reports from Cairo say dozens of people have been killed as Egyptian security forces move in on two sit-in protests supporting ousted Islamist President Mohamed Morsi.
Media sources quoted pro-Morsi groups as saying at least 25 people were killed in the violence. Egyptian state media say at least two security force members have been killed in the melee.
The casualty figures could not be independently confirmed.
Police backed by bulldozers and armored cars, fired tear gas at the protest sites. Television footage shows smoke rising over the protest site and military helicopters circling in the sky. State media say some 35 protesters have been arrested for having gas cans or cylinders.
Reports say the Nahda Square protest site, near Cairo University, has been completely cleared of demonstrators and soldiers have sealed off the roads leading to the university.
Layla Moustafa, an activist in the anti-coup alliance, tells VOA the movement by security forces started early in the morning.
"There were snipers situated on rooftops of buildings near Rabaa. The shootings and dispersals started from approximately seven in the morning today and are ongoing until now."
She said Wednesday's actions will not quell the outcry against Morsi's opponents.
"Already, protesters are taking to the streets right now, nationwide, in all cities. There have been ongoing protests since yesterday nationwide in all governates."
Officials and witnesses said the unrest began Tuesday when hundreds of Morsi supporters marched on several ministries to protest the military-backed interim government installed after the military deposed Mr. Morsi on July 3.
Local residents and shopkeepers who backed the ouster threw stones at Morsi supporters marching on the Interior Ministry. The protesters retaliated with stones and police fired tear gas to try to break up street confrontations between Morsi's supporters and opponents.
Other supporters of the former president remained at two Cairo protest camps, defying days of warnings that the government may soon try to evict them.
More than 250 people have been killed in political violence since Mr. Morsi's overthrow.
The interim civilian government is moving ahead with a transition plan that involves reforming Egypt's constitution and holding elections early next year.