Thousands of anti-government protesters, some hurling rocks and climbing atop an armored police truck, clashed with riot police Tuesday in the center of Cairo in a Tunisia-inspired demonstration to demand the end of Hosni Mubarak's nearly 30 years in power.Police responded with blasts from water cannons and set upon crowds with batons and acrid clouds of tear gas to clear demonstrators crying out "Down with Mubarak" and demanding an end to Egypt's grinding poverty, corruption, unemployment and police abuses.
Tuesday's demonstration, the largest Egypt has seen for years, began peacefully, with police showing unusual restraint in what appeared to be a calculated strategy by the government to avoid further sullying the image of a security apparatus widely seen as little more than corrupt thugs in uniforms.
As crowds carrying Egyptian and Tunisian flags filled downtown Cairo's main Tahrir square, however, security personnel changed tactics and the protest turned violent. The scenes had particular resonance because Tuesday was also a national holiday honoring the much-feared police.
Demonstrators attacked a water cannon truck, opening the driver's door and ordering the man out of the vehicle. Some hurled rocks and dragged metal barricades. Officers beat back protesters with batons as they tried to break cordons to join the main group of demonstrators downtown.
Protesters emerged stumbling from white clouds of tear gas, coughing and covering their faces with scarves.
Some had blood streaming down their faces. One man fainted. Police dragged some away and beat a journalist, smashing her glasses and seizing her camera.
At one point, the protesters seemed to gain the upper hand, forcing a line of riot police to flee under a barrage of rocks. One demonstrator climbed into a fire engine and drove it away.
To the north, in the Mediterranean port city of Alexandria, thousands of protesters also marched in what was dubbed a "Day of Rage" against Mubarak and lack of political freedoms under his rule.
Like the Tunisian protests, the calls for the rallies in Egypt went out on Facebook and Twitter, with 90,000 saying they would attend. Organizers used the site to give minute-by-minute instructions on where demonstrators should go in an attempt to outmaneuver the police.
By late afternoon, access to Twitter appeared to have been blocked.
In another parallel with Tunisia, the protests drew energy in large part from the death of one person: a young Egyptian man named Khaled Said whose family and witnesses say was beaten to death by a pair of coppers in Alexandria last year.
His case has become a rallying point for Egypt's opposition. Two coppers are on trial in connection with his death.
Tunisia's protests were also sparked by the death of one man: a poor Tunisian vegetable vendor who set himself in fire to protest corruption.
Last week, several people in Egypt -- and elsewhere in the Middle East and North Africa -- set themselves on fire in apparent attempts to copy his actions.