Three people were killed as troops fought daylong battles with protesters, showing the tensions seething in Egypt nine months after Hosni Mubarak's fall, even in the midst of polls meant to herald a promised transfer to civilian rule.
The Health Ministry said 257 people had also been wounded in the clashes in Cairo on Friday, where anger at the actions of the security forces turned the city centre into a smoke-filled battleground shortly after two days of mostly peaceful voting.
Egypt's Dar al-Iftah, the body that issues Islamic fatwas (edicts), said one of its top officials, Emad Effat, was among the dead, the state news agency MENA said.
The violence has sharpened tensions between the ruling army and its opponents, and clouded a parliamentary vote set to bring Islamists, long repressed by Mubarak, to the verge of power.
Clashes around the cabinet offices and parliament raged on after nightfall, with protesters throwing petrol bombs and stones at soldiers who used batons and what witnesses said appeared to be electric cattle prods.
Some of the casualties had gunshot wounds, but the ruling military council, in a statement read on state television, denied that troops had used firearms and rejected accusations by pro-democracy activists that the army had ignited the unrest by trying to disperse a sit-in outside the cabinet office.
The army said the trouble had begun when an officer tasked with maintaining security outside parliament had been attacked.
A new civilian advisory council set up to offer policy guidance to the generals said it would resign if its recommendations on how to solve the crisis were not heeded.
One of its members, presidential candidate Amr Moussa, told an Egyptian television channel that the body had suspended its meetings until the military council met its demands, including halting all violence against demonstrators.
Islamist and liberal politicians decried the army's tactics.
"Even if the sit-in was not legal, should it be dispersed with such brutality and barbarity?" asked Mohamed ElBaradei, a presidential candidate and former UN nuclear watchdog head.
The sit-in outside the cabinet office was a remnant of far bigger protests last month around Cairo's Tahrir Square in which 42 people were killed shortly before voting began in Egypt's first election since the army council took over from Mubarak.
"The council wants to spoil the elections. They don't want a parliament that has popular legitimacy, unlike them, and would challenge their authority," said Shadi Fawzy, a pro-democracy activist. "I don't believe they will hand over power in June."
A big turnout in the first round of the election, which began on Nov. 28, had partly deflated street protests against army rule. But the unrest had already prompted the government to resign and the generals to pledge to step aside by July.
The army is in charge until a presidential election in June, but parliament will have a popular mandate that the military will find hard to ignore as it oversees the transition.
On Sunday, a new cabinet is to hold its first full meeting since it was sworn in on Dec. 7 and plans to weigh new austerity measures to address a wider-than-expected budget deficit.
But the latest violence may make it even harder for Prime Minister Kamal al-Ganzouri, who has made law and order a priority for his interim government, to gain credibility.
Adel Soliman, head of Cairo's International Centre for Future and Strategic Studies, said Ganzouri had not responded decisively to the crisis despite saying his government had wide authority. "There is complete silence from all those in power."
Want to enjoy 'Zen' reading - with no ads and just the article? Subscribe todaySubscribe now