Tens of thousands of protesters have clashed with police across Egypt in the most violent scenes yet in the challenge to President Hosni Mubarak's 30-year rule.
One protester was killed and pro-reform leader and Nobel Peace Prize winner Mohamed ElBaradei was placed under house arrest after joining demonstrations, while Egyptian state TV announced a 6pm to 7am curfew in Cairo and two other cities.
Groups of thousands of protesters, some chanting "out, out, out", defied a ban on any gatherings and turned out at different venues across Cairo, while security officials said there were protests in at least 11 of the country's 28 provinces.
It was a major escalation in the movement that began on Tuesday to demand the removal of 82-year-old Mr Mubarak and vent rage at years of government neglect over rampant poverty, unemployment and rising food prices.
Security officials said protesters ransacked the headquarters of Mr Mubarak's ruling party in the cities of Mansoura, north of Cairo, and Suez, east of the capital. Internet and mobile phone services were largely cut off in an apparent bid to hinder the protest organisers.
Some of the most serious violence was in Suez, where protesters seized weapons stored in a police station and asked the policemen inside to leave the building before they burned it down and also set ablaze about 20 police trucks parked nearby.
Demonstrators exchanged fire with policemen trying to stop them from storming another police station and one protester was killed in the gun battle, bringing the death toll from four days of protests to eight.
The protesters were energised by the return of Mr ElBaradei, one of the leading pro-democracy advocates, who returned on Thursday night after a month abroad, declaring he was prepared to lead the opposition to a regime change.
When he joined protesters on Friday following noon prayers, police fired water cannon at him and his supporters and used batons to beat some of Mr ElBaradei's supporters, who surrounded him to protect him.
A soaking wet Mr ElBaradei was trapped inside a mosque while hundreds of riot police laid siege to it, firing tear gas in the streets around so no one could leave. When Mr ElBaradei returned home police stationed outside told him he was not allowed to leave again.