Raw Video: Out-of-Control Violence in Egypt

CAIRO (AP) -- President Hosni Mubarak imposed a night curfew and signaled he was about to send the military out in the streets for the first time to quell an unprecedented challenge to his regime by tens of thousands of protesters who rioted on Friday. One demonstrator was killed and even a Nobel Peace laureate was placed under house arrest after joining the protests.

State television said the curfew would be in force from 6 p.m. to 7 a.m. in Cairo, the Mediterranean port city of Alexandria and the flashpoint city of Suez east of the capital. It said the military will work in tandem with the police to enforce the ban.

It was the most drastic measure so far to quell daily riots and protests that began Tuesday and spiraled into chaos on Friday after noon prayers.

Groups of thousands of protesters, some chanting "out, out, out," defied a ban on any gatherings and turned out at different venues across Cairo, a city of about 18 million people. Some marched toward major squares and across scenic Nile bridges. Burning tires sent up plumes of black smoke across the cityscape as the sun set.

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. Demonstrators exchanged fire with policemen trying to stop them from storming another police station and one protester was killed in the gun battle.

The death brought the toll of those killed in four days of protests to eight.