Cairo police fought protesters demanding an end to army rule for a third day on Monday and morgue officials said the death toll had risen to 33, making it the worst spasm of violence since the uprising that toppled President Hosni Mubarak.
The bloodshed in and around Cairo's Tahrir Square, epicentre of the anti-Mubarak revolt, threatens to disrupt Egypt's first free parliamentary election in decades, due to start next week.
Clashes have raged on and off since police used batons and tear gas to try to disperse a sit-in in Tahrir on Saturday.
Protesters have brandished bullet casings in the square, but police deny using live fire. Medical sources at Cairo's main morgue said 33 corpses had been received there since Saturday, most of them with bullet wounds. At least 1,250 people have been wounded, a Health Ministry source said.
I've seen the police beat women my mother's age. I want military rule to end, said 21-year-old Mohamed Gamal. I will just go home in the evening to change my clothes and return.
Islamists dominated demonstrations against army rule on Friday, but the unrest in Tahrir since then has drawn in many of the young activists who helped topple Mubarak on February 11.
Army generals were feted for their part in easing him out, but hostility to their rule has hardened since, especially over attempts to set new constitutional principles that would keep the military permanently beyond civilian control.
Police attacked a makeshift hospital in the square after dawn on Monday but were driven back by protesters hurling chunks of concrete from smashed pavements, witnesses said.
Don't go out there, you'll end up martyrs like the others, protesters told people emerging from a metro station at Tahrir Square, where about 4,000 had gathered by midday.
CLOUD OVER ELECTION
The violence casts a pall over the first round of voting in Egypt's staggered and complex election process, which starts on November 28 in Cairo and elsewhere. The army says the polls will go ahead, but the unrest could deter voters in the capital.
Some Egyptians, including Islamists who expect to do well in the vote, say the ruling army council may be stirring insecurity to prolong its rule, a charge the military denies.
German Foreign Minister Guido Westerwelle called for an end to the violence. This is quite evidently an attempt to thwart a democratic transition process and we are opposed to that attempt, he said.
Political uncertainty has gripped Egypt since Mubarak's fall, while sectarian clashes, labour unrest, gas pipeline sabotage and a gaping absence of tourists have paralysed the economy and prompted a widespread yearning for stability.
The state news agency MENA said 63 flights to and from Cairo had been cancelled because of the latest unrest.
The military plans to keep its presidential powers until a new constitution is drawn up and a president is elected in late 2012 or early 2013. Protesters want a much swifter transition.
The army said on Monday it had intervened in central Cairo to protect the Interior Ministry, not to clear demonstrators from nearby Tahrir Square, whom it also offered to protect.
The protesters have a right to protest, but we must stand between them and the Interior Ministry, said General Saeed Abbas. The armed forces will continue in their plans for parliamentary elections and securing the vote.
The Interior Ministry, in charge of a police force widely hated for its heavy-handed tactics in the anti-Mubarak revolt, has been a target for protesters demanding police reform.
Unfortunately the Interior Ministry still deals with protests with the same security mentality as during Mubarak's administration, said military analyst Safwat Zayaat.
The latest street clashes show the depth of frustration, at least in Cairo and some other cities, at the pace of change.
Military rule is defunct, defunct, crowds chanted. Freedom, freedom.
Internet clips, which could not be verified, showed police beating protesters with sticks, pulling them by the hair and, in one case, dumping what looked like a body on a rubbish heap.
Residents reacted angrily when police fired tear gas into a crowd gathered below a burning building 200 metres (yards) from Tahrir Square, hindering the rescue of trapped residents.
Outside the burning apartment building, protesters chanted Tantawi burnt it and here are the revolutionaries, referring to Field Marshal Mohamed Hussein Tantawi, Mubarak's defence minister for two decades and leader of the army council.
I don't want Tantawi ... I am staying tonight, said Ayman Ramadan, a data entry clerk, said early on Monday morning.
Doctors in orange vests were treating casualties on pavements in the middle of Tahrir.
The April 6 Youth movement told MENA it would stay in Tahrir and pursue sit-ins in other cities until its demands were met, including one for a presidential vote by April.
Other demands include replacing the cabinet with a national salvation government and an immediate investigation into the clashes in Tahrir and trial of those implicated in it.
Presidential candidate Hazem Salah Abu Ismail, a Salafi Islamist, told protesters: We are demanding as the minimum that power be handed over within six months.
Presidential hopefuls Mohamed ElBaradei and Abdallah al-Ashaal denounced violence against protesters and called for a national salvation government, MENA said.
Liberal groups are dismayed by the military trials of thousands of civilians and the army's failure to scrap a hated emergency law. Islamists eying a strong showing in the next parliament suspect the army wants to curtail their influence.
Analysts say Islamists could win 40 percent of assembly seats, with a big portion going to the Muslim Brotherhood.
(Additional reporting by Erik Kirschbaum; writing by Alistair Lyon; editing by Philippa Fletcher)