A masked protester throws a gas canister towards Egyptian riot police, not seen, near the interior ministry during clashes in downtown Cairo, Egypt, on November 20, 2011. Firing tear gas and rubber bullets, Egyptian riot police on Sunday clashed for a second day with thousands of rock-throwing protesters demanding that the ruling military quickly announce a date to hand over power to an elected government. #

Tens of thousands of Egyptians gather during a demonstration at Tahrir Square in Cairo, on November 18, 2011. Over 50,000 Egyptian protesters flocked to Cairo's Tahrir square on Friday to pressure the military government to transfer power to elected civilian rule, after the cabinet tried to enshrine the army's role in a constitutional proposal. #

Tens of thousands of Egyptian protesters wave national flags during a rally held in Cairo's landmark Tahrir Square on November 18, 2011 with the aim of pushing Egypt's ruling military to cede power, 10 months after an uprising that toppled Hosni Mubarak's regime. #

Ahmed Abu Duma, an activist and opposition writer, flashes a peace sign front of Egyptian riot police during clashes at Tahrir Square in Cairo, on November 19, 2011. #

Egyptian riot police clash with protesters in Tahrir Square in Cairo, Egypt, on November 19, 2011. Egyptian riot police beat protesters and dismantled a small tent city set up to commemorate revolutionary martyrs in Cairo's Tahrir Square on Saturday. #

A member of security forces stands along a street with debris and fire as the army try to disperse protesters in Cairo, on November 20, 2011. Police backed by the army used batons and teargas on Sunday to charge protesters in Cairo's Tahrir Square demanding Eygpt's ruling generals swiftly hand power to civilians, in some of the worst violence since the overthrow of Hosni Mubarak. #

A protester overcome with tear gas inhalation sits on the curb during clashes with the Egyptian riot police near the interior ministry in downtown Cairo, on November 20, 2011. #

A protester, with spent ammunition casings on his fingers, flashes the victory sign in front of a burning building during clashes with police at a road, which leads to the Interior Ministry, near Tahrir Square, on November 21, 2011. #

A protester sits inside broken windows in a damaged building belonging to The American University in Cairo as he watches the clashes at a road, which leads to the Interior Ministry, near Tahrir Square, on November 21, 2011. #

Protesters take cover behind makeshift barricades as riot police fire tear gas and rubber-covered bullets in a side street near Tahrir Square in Cairo, on November 21, 2011. #

A riot policeman aims a shotgun with rubber bullets at protesters, next to plainclothes policemen during clashes in a side street near Tahrir Square in Cairo, on November 21, 2011. #

Protesters carry a man injured during clashes with riot police firing tear gas and rubber-covered bullets in a side street near Tahrir Square in Cairo, on November 21, 2011. #

A protester carries stones to throw during clashes with Egyptian riot police near Tahrir Square in Cairo, Egypt, on November 21, 2011. Security forces fired tear gas and clashed Monday with several thousand protesters in Cairo's Tahrir Square in the third straight day of violence that has killed more than two dozen people and has turned into the most sustained challenge yet to the rule of Egypt's military. #