Clashes have again erupted in the Egyptian capital as security forces continue their efforts to clear Cairo's Tahrir Square of protesters.
At least 33 people are reported to have have died since the violence began on Saturday with hundreds more injured.
Protesters fear the interim military government is trying to retain its grip on power.
Culture Minister Emad Abu Ghazi has resigned in protest at the government's handling of the demonstrators.
On Monday, 25 Egyptian political parties also called for the ministers of information and the interior to be sacked over the violence.
The Supreme Council of the Armed Forces, led by Field Marshal Mohamed Tantawi, is charged with overseeing the country's transition to democracy after three decades of autocratic rule under ousted President Hosni Mubarak.
Calls for Field Marshal Tantawi's resignation could be heard during the weekend's protests.
It is the longest continuous protest since President Mubarak stepped down in February and casts a shadow over elections due to start next week.
Large crowds were again seen streaming into Tahrir Square on Monday – defying the military's attempts to keep them away from the place that was the symbolic heart of demonstrations against Mr Mubarak.
TV footage showed tear gas being fired into the protesters, while fire bombs and chunks of concrete were reportedly being lobbed back at the police.
During clashes overnight, a makeshift field hospital – one of a number set up in and around the square – was reportedly attacked by police.
And as the violence continued into Monday morning, tear gas fired by police reportedly set light to a nearby apartment block.
The clashes followed fierce fighting on Sunday.
Violence also took place in other cities over the weekend, including Alexandria, Suez and Aswan.
The health ministry said that 20 people had been killed on Sunday and Monday, with two people killed on Saturday. Some 1,750 people have been injured.
Morgue officials said later on Monday that the death toll was now at least 33.
Amr Moussa, former secretary-general of the Arab League and now a presidential candidate in Egypt, told the BBC World Service that the use of force against the protesters could not be justified.
"The way the police deals with the protesters… we're all against this kind of violence and this treatment of the people," he said.
"You cannot justify any amount of the use of force against the civilians expressing their own point of view."
He said the military council needed to end the uncertainty surrounding parliamentary and presidential elections.
Earlier, Culture Minister Emad Abu Ghazi resigned "in protest at the government's handling of the recent events in Tahrir Square", Egypt's official Mena news agency reports.
The BBC's Yolande Knell in Cairo says the demands of the protesters have changed over the course of the weekend. Crowds initially gathered to urge the military to set a date for the handover of power, but now they want the military leaders to resign immediately and hand over to a civilian administration.
"The military promised that they would hand over power within six months," one protester said. "Now 10 months have gone by and they still haven't done it. We feel deceived."
In recent weeks, protesters – mostly Islamists and young activists – have been holding demonstrations against a draft constitution that they say would allow the military to retain too much power after a new civilian government is elected.
Earlier this month, the military council produced a draft document setting out principles for a new constitution, under which the military and its budget could be exempted from civilian oversight.
A proposal by the military to delay the presidential election until late 2012 or early 2013 has further angered the opposition.
Protesters want the presidential vote to take place after parliamentary elections, which begin on 28 November and will be staggered over the next three months.
A statement from the cabinet on Sunday said the elections would go ahead as planned, and praised the "restraint" of interior ministry forces against protesters.
The military council, in a statement read out on state television, said it "regretted" what was happening, AFP news agency reports.