CAIRO – Tens of thousands of anti-government protesters poured into the streets of Egypt Friday, stoning and confronting police who fired back with rubber bullets and tear gas in the most violent and chaotic scenes yet in the challenge to President Hosni Mubarak's 30-year rule. Even a Nobel Peace laureate was placed under house arrest after joining the outraged demonstrators.

Groups of thousands of protesters, some chanting "out, out, out," gathered at different venues across Cairo, a city of about 18 million people, some marching toward major squares and across scenic Nile bridges. 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 82-year-old Mubarak's ouster and vent rage at years of government neglect of rampant poverty, unemployment and rising food prices. Security officials said protesters ransacked the headquarters of Mubarak's ruling party in the cities of Mansoura north of Cairo and Suez, east of the capital.

Some of the most serious violence Friday 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. They also set ablaze about 20 police trucks parked nearby.

Internet and cell phone services, at least in Cairo, appeared to be largely cut off since overnight in the most extreme measure so far to try to hamper protesters form organizing. However, that did not prevent tens of thousands from flooding the streets, emboldened by the recent uprising in Tunisia — another North African Arab nation.

It's time for this government to change," said Amal Ahmed, a 22-year-old protester. "I want a better future for me and my family when I get married.