Military forces have deployed on the streets of Cairo as thousands of antigovernment protesters clashed with police in the most violent scenes yet in the challenge to President Hosni Mubarak's 30-year rule.
Egypt Erupts

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Masked Egyptian demonstrators hold the national flag as they stand next to a burning police vehicle in Cairo.

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Egyptian demonstrators fuel the fire next to burning police vehicles in Cairo.

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A man identified as a police officer, overcome by tear gas, is helped by antigovernment demonstrators.

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A protester gestures during protests in Cairo on January 28.

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A protester walks in front of a burning police vehicle in Cairo on January 28.

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Demonstrators brave police water cannons and tear gas during a protest in Cairo on January 28.

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Burning barricades during a demonstration in Cairo on January 28.

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A plainclothes policeman confronts a foreign journalist during a demonstration in Cairo on January 28.

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Demonstrators perform Friday Prayers in front of riot police during a demonstration in Cairo on January 28.

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Antigovernment protesters confront riot police in Cairo on January 28.

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A demonstrator confronts a riot policeman wearing a gas mask after Friday Prayers in Cairo on January 28.

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Antigovernment protesters confront riot police during a demonstration in Cairo on January 28.

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Antigovernment protesters run from tear gas as they confront riot police in Cairo on January 28.

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Demonstrators suffering from tear gas hide in a mosque following a demonstration in Cairo on January 28.

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Muhammad El-Baradei is surrounded by demonstrators in Cairo on January 28.

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Antigovernment protesters confront riot police in Cairo on January 28.

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Muhammad El-Baradei in a mosque after riot police used water cannons to disperse demonstrators on January 28.

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A protester shouts in front of a burning barricade during a demonstration in Cairo on January 28.