Cairo: Clashes between supporters and opponents of ousted President Mohammad Morsi has killed at least 19 people and injured over 700 across the country, with violence continuing into the early hours of Saturday, Xinhua reported.
Police arrested 53 Morsi-supporters who were carrying guns, Molotov cocktails and other weapons, according to official news agency MENA.
In the capital, tens of thousands of Egyptians gathered at downtown Cairo's Tahrir Square and around the presidential palace in Heliopolis to show their support for the military, which has played a central role in removing Morsi from power.
Similar gatherings of Morsi-opponents were also staged in various cities across the country.
Meanwhile, loyalists of the deposed president rallied in Nasr City's Rabia al-Adawiya Square, Giza's Nahda Square near Cairo University and in some other provinces.
The number of pro-military protesters nationwide was estimated at 29 million, based on data collected by satellites and military helicopters, official news agency MENA quoted a security source as saying.
In Cairo's Shubra district, sporadic clashes left at least over a dozen people injured, with some of them suffering gunshot wounds. Elsewhere in the governorates of Gharbiya and Damietta, clashes between the two sides injured at least 18.
In contrast to relative calmness in Cairo, Alexandria has seen a much violent confrontation between the two rival groups. At least five people were killed and over 100 were injured, mostly wounded by gunshots and birdshots, according to a local hospital manager.
Similar clashes erupted in Luxor and Fayoum governorates and lasted into the early hours of Saturday, leaving at least 16 injured. Two vehicles belonged to Muslim Brotherhood members were burned.
Earlier Friday, an investigating judge ordered detention of ousted Morsi for 15 days over charges of spying and jailbreak in 2011, during the popular uprising that toppled ex-president Hosni Mubarak.
Interim President Adli Mansour on the same day urged Morsi's supporters to end their sit-in. "Go back home and I personally promise that no one will legally pursue you," he said in a phone interview with a local TV channel on Friday evening.
Outside the presidential palace, Interim Prime Minister Hazem al-Beblawi and some of his ministers joined the pro-military demonstration called on by Defense Minister Abdel- Fattah al-Sisi on Wednesday.
Sisi's call for Egyptians to take to the streets is a message to the whole world to show that the majority of Egyptians reject violence and terrorism, and that they are against such practices as blocking roads or disturbing social order, said Culture Minister Mohamed Saber.
Mohamed ElBaradei, vice president for foreign relations, said Friday it was time to end political polarization in Egypt, to renounce violence and to return to the rule of law.
"We must exercise tolerance and rebuild the nation with participation of every Egyptian citizen," ElBaradei said on his official Twitter account.
Amr Moussa, leader of the liberal Conference Party, expressed satisfaction that millions of people, via their presence in Friday's mass rallies, have expressed confidence in the armed forces and the interior ministry to take necessary measures to combat terrorism.
"The crowds sent a clear message to those who think they can play with the Egyptian national security," he added.
Nader Bakkar, spokesperson for the conservative Salafist Al-Nour Party, said that Friday marches showed persistence of Egyptians to move forward, adding elected institutions should be built swiftly.
"Al-Nour Party is making mediation efforts between the army and leaders of the Muslim Brotherhood to resolve the ongoing crisis," he said.