Clockwise: Fires from burning buildings are seen at night on the Corniche in downtown Cairo, Egypt, Friday; A protester stands in front of a burning barricade during a demonstration; A young protester throws a missile during a demonstration in Suez. (AP/Reuters)n Tanks roll into Cairon Protesters defy curfewn EgyptAir suspends flightsCAIRO: President Hosni Mubarak sacked Egypt's government and vowed to bring in democratic measures, in an address to the nation early Saturday after several days of deadly protests. He called anti-government protests part of plot to destabilize Egypt and destroy the legitimacy of his regime. Earlier on Friday, tanks moved on to the streets of Cairo and Alexandria as protesters in Egypt defied a nationwide curfew imposed in an effort to quell the fourth and most violent day of demonstrations. However, official MENA news agency later Friday withdrew its announcement that a curfew had been extended nationwide, while state television said it applied to Cairo, Alexandria and Suez. Despite the night-time curfew, thousands stayed out on the streets of Cairo, Alexandria and Suez; some thronged around mounted armored cars, cheering and waving flags. Medical sources said at least five protesters had been killed and 870 wounded on a day that saw security forces using rubber bullets, tear gas and water cannon to disperse crowds. Demonstrations involving tens of thousands of people were the biggest and bloodiest in four consecutive days of protests. The unrest hit global financial markets. Investors turned to the dollar and US Treasuries as safe havens, while stocks fell around the world and crude oil prices rose. Friday evening marked the first time the army had been put onto the streets. It was not immediately clear what role it would play or how troops would react to the protesters. A Reuters photographer saw people entering one of the buildings belonging to the National Democratic Party and walking out with chairs, carpets and other items. As darkness fell, tracked armored cars took up positions in key cities. “The armed forces started to deploy forces in the governorates of Cairo, Alexandria and Suez as a first stage in implementing the decree...imposing a curfew starting from 6 P.M.,” the official news agency reported. Some 2,000-3,000 people encircled a military vehicle near Cairo's Tahrir Square, a Reuters witness said. They climbed on it, shaking hands with the soldiers, and chanted: “The army and the people are united”. Shots were heard near parliament and TV showed the headquarters of the ruling party in flames, the blaze lighting up the night sky. Al Arabiya television said protesters forced their way into the state television building, but broadcasts there continued as normal. In the eastern city of Suez, site of the strategically crucial canal, armored cars deployed in front of the charred remains of a police station, a Reuters witness said. He said the offices of the telecoms company Vodaphone were looted. Dozens of protesters climbed on the military vehicles in Suez. They talked to soldiers who attempted to wave them off. Secretary of State Hillary Clinton said Washington was deeply concerned by violence used by the security forces against the protesters and she urged the government to restrain them. Snatch squads of plain clothes security men dragged off suspected ringleaders. At the Fatah mosque in central Ramses Square in Cairo, several thousand people were penned in and teargassed. Protesters often quickly dispersed and regrouped. Prominent activist Mohamed ElBaradei, a Nobel Peace Laureate, was briefly penned in by police after he prayed at a mosque in the Giza area but he later took part in a peaceful march with supporters. Arabiya television said later police had “asked” him to stay home but this could not be confirmed. In some parts of Cairo, protests were peaceful. Dozens of people prayed together on one road. In Giza, on the city outskirts, marchers shook hands with the police who let them pass peacefully. Before Friday's clashes, at least five people had been killed over the four days, one of them a police officer. Police have arrested several hundred people. Members of the Muslim Brotherhood opposition group, including at least 8 senior officials, were rounded up overnight. The government has accused the Brotherhood of planning to exploit the protests. Many protesters are young men and women. Two thirds of Egypt's 80 million people are below 30 and many have no jobs. About 40 percent of Egyptians live on less than $2 a day. Meanwhile, Egypt's national carrier temporarily suspended its flights from the capital, while international airlines scrambled to readjust their schedules to accommodate the curfew. The curfew presented international airlines with a problem. Many flights in Cairo arrive late in the evening or in the pre-dawn hours. Several international airlines said they were working to reschedule their flights to ensure that their passengers arrived outside the curfew. An official at Cairo's international airport said some foreign airlines had canceled or rerouted flights slated to arrive Friday night, including Air France.