Clashes were ongoing on Youssef al-Guindy and Mohamed Mahmoud streets well into the early hours of Sunday, where protesters and security forces faced off near the Interior Ministry in downtown Cairo.
Security forces used intense amounts of tear gas in an attempt to disperse protesters, who responded by hurling rocks and Molotov cocktails.
Earlier on Saturday, clashes took place on Qasr al-Aini Street between security forces and protesters in front of the Shura Council, and raged for hours as they spread to other streets surrounding Tahrir.
Violence has been ongoing in cities across Egypt since Friday, starting with clashes that broke out on the 25 January anniversary, when mass protests took place denouncing the Muslim Brotherhood's monopolization of power. Nine people were killed, mainly in Suez, where the army has been deployed.
The 6 October Bridge was blocked off intermittently Saturday evening and the fighting also reached the Garden City Corniche near the Qasr al-Nil entrance and the Semiramis Hotel, all the way down to Simon Bolivar Square. Tear gas was heavy in the whole area.
A security source said that the management of the three nearby hotels — the Semiramis and Shepherd hotels on one side, as well as the Hilton Ramsis overlooking Abdel Moneim Riad Square — were asked to close the gates and not allow anyone to enter or exit.
A fire that broke out late Saturday at the Lycee School on Sheikh Rihan Street had been contained, the same street where clashes had been taking place throughout the day. A security source told Al-Masry Al-Youm that the fire ravaged three classrooms and the school's basement. There were also reports of a fire at the Misr Insurance office in Talaat Harb Square.
Late into the night, Tahrir was relatively and cautiously calm as fighting continued in surrounding streets, and the number of protesters there decreasing significantly.
There were also several reports of random arrests made during the day's clashes.
Mohamed el-Beltagi, a leading member of the Muslim Brotherhood, called on President Mohamed Morsy to announce a state of emergency if necessary to contain the violence and "thuggery" that has engulfed several cities in Egypt.
He also called on Morsy and the prime minister, as well as the ministers of defense and interior, to intervene immediately with "strength and determination" to protect citizens' lives, prevent arson attacks against government institutions and stop protests from blocking roads, using all legitimate means.
The National Salvation Front, meanwhile, has said they will boycott the upcoming elections for the House of Representatives if Morsy does not meet their demands to form a "national salvation" government.
In a statement, the NSF said Egyptians should rally against the new Constitution and is calling for an unbiased committee to amend disputed articles in it.
The Front held Morsy responsible for deaths during the violence that has taken place in Ismailia, Port Said and Suez, as a result of protests commemorating the 25 January revolution and protests against the death sentence for 21 defendants in the Port Said trial.
The Port Said clashes death toll reached at least 31, according to the Ministry of Health, with more than 300 injured.
The National Defense Council, which is led by Mursi and includes the defense minister who commands the army, called for "a broad national dialogue that would be attended by independent national characters" to discuss political differences and ensure a "fair and transparent" parliamentary poll.