In scenes reminiscent of the 18-day uprising that toppled Hosni Mubarak from three decades of power in February, hundreds of youths chanted "The people want to topple the regime" on Saturday as they rushed towards riot police, who fired rubber bullets and tear gas.
Protesters broke chunks of cement from pavements and hurled them at police in clashes in which police lost control of Cairo's landmark Tahrir Square twice in the day.
A blaze broke out around midnight at the huge Mogamma state administration building overlooking Tahrir.
As police fired round after round of tear gas at protesters near the interior ministry, closer to Tahrir protesters laid sheets of metal to block roads into the square.
"They unleashed 20 trucks to forcefully disperse a few dozen peaceful protesters this morning," Salah Saeed said as he handed out vinegar-doused napkins to protect protesters against the tear gas.
"Now thousands of Egyptians are protesting in Tahrir. We don't need the corrupt interior ministry or the military council," he said.
Staggered voting is due to begin on Nov. 28 but could be disrupted if violence spreads.
The vote is being overshadowed by a row between political parties and the government over ground rules for a draft constitution that could leave the army free of civilian control.
The army won popular backing during Mubarak's overthrow for maintaining order and pledging to hand power to an elected government, but support has ebbed over its use of military trials for civilians and suspicion that it wants to continue to wield the levers of power after a new government is sworn in.
A security official said on Saturday police had used lawful methods to deal with "troublemakers". Protesters said they were incensed by brutal police tactics to break up a peaceful sit-in.
State news agency MENA quoted the health ministry's spokesman as saying 676 people had been hurt in Cairo and that Ahmed Mahmoud, a 23-year-old demonstrator, died in hospital. MENA reported another death in Egypt's second city Alexandria.
The army stayed away from the fighting.