Five people were killed and scores hurt on Friday in confrontations between supporters and opponents of ousted Egyptian President Mohammed Morsi, who was pushed out July 3 in a military coup.
The worst of the violence unfolded around a mosque in central Alexandria, where clashes left five dead and 147 injured.
Tens of thousands of people gathered in Cairo's Tahrir Square - birthplace of the February 2011 revolution that toppled strongman Hosni Mubarak - in response to a call from Egypt's armed forces chief for citizens to take to the streets in support of the security forces.
Friday evening marked the end of the 48 hours Gen. Abdel Fattah al-Sisi gave Egyptians "to join the ranks of the homeland" or prepare to see the military adopt an unspecified new approach to dealing with protests.
The flag-waving crowd in Tahrir Square cheered the news that a judge ordered Morsi jailed on suspicion of various offenses, including murder.
The deposed president is thought to be in military custody.
Thousands of Islamists congregated in Cairo's Nasr City neighborhood to express support for Morsi and listen to an address by influential cleric Safwat al-Hijazi, who is wanted on allegations of involvement in violent acts.
Al-Hijazi told Efe he has no intention of surrendering to authorities and vowed the Islamists would continue their protest in Nasr City.
"We challenge them (the army) to come to kill us and dismantle the protest," he said. "We will not kill and none of us will resist."
Morsi won the presidency in a democratic election, but alienated many Egyptians by his failure to remedy the country's economic woes and an agenda that was seen as too subservient to the Muslim Brotherhood.
The army forced him from office after days of large anti-government demonstrations. EFE