Thousands of Egyptian protesters gather for a demonstration in Cairo's landmark Tahrir Square on January 25, 2013. Thousands of Egyptians marched on Tahrir Square to demand change, two years after the uprising that ousted Hosni Mubarak and ushered in an Islamist government, as sporadic clashes erupted nearby.
- [MOHAMMED ABED/AFP/Getty Images]

Egyptian men take part in midday prayer during a demonstration in Tahrir Square on January 25, in Cairo, Egypt. Thousands of protesters converged on the capital's iconic Tahrir Square on Friday to mark the second anniversary of the overthrow of former President Hosni Mubarak's regime.
- [Ed Giles/Getty Images]

Egyptian protesters run away from a tear gas canister fired by Egyptian security forces during clashes with riot police in Tahrir Square on January 25, in Cairo, Egypt. Thousands of protesters converged on the capital's iconic Tahrir Square on Friday to mark the second anniversary of the overthrow of former President Hosni Mubarak's regime.
- [Ed Giles/Getty Images]

An injured Egyptian protester is led away from clashes with riot police in Tahrir Square on January 25, in Cairo, Egypt. Thousands of protesters converged on the capital's iconic Tahrir Square on Friday to mark the second anniversary of the overthrow of former President Hosni Mubarak's regime.
- [Ed Giles/Getty Images]

Egyptian men take part in midday prayer during a demonstration in Tahrir Square on January 25, in Cairo, Egypt. Thousands of protesters converged on the capital's iconic Tahrir Square on Friday to mark the second anniversary of the overthrow of former President Hosni Mubarak's regime.
- [Ed Giles/Getty Images]

Thousands of Egyptian protesters gather for a demonstration in Cairo's landmark Tahrir Square on January 25, 2013. Thousands of Egyptians marched on Tahrir Square to demand change, two years after the uprising that ousted Hosni Mubarak and ushered in an Islamist government, as sporadic clashes erupted nearby.
- [MOHAMMED ABED/AFP/Getty Images]

An Egyptian protester lights flares during a demonstration in Cairo's landmark Tahrir Square on January 25, 2013. Thousands of Egyptians marched on Tahrir Square to demand change, two years after the uprising that ousted Hosni Mubarak and ushered in an Islamist government, as sporadic clashes erupted nearby.
- [MOHAMMED ABED/AFP/Getty Images]

An Egyptian protester wave a flag siiting on a branch during a protest in Tahrir Square on January 25, 2013 in Cairo. Huge crowds are expected to demonstrate in Egypt on the second anniversary of the revolution that ousted Hosni Mubarak and brought in an Islamist government, as political tensions simmer and economic woes bite.
- [MOHAMMED ABED/AFP/Getty Images]

Egyptian protesters throw stones towards security forces in Cairo's Tahrir Square, on January 25, 2013. Thousands of Egyptians marched in Tahrir Square to demand change, two years after the uprising that ousted Hosni Mubarak and ushered in an Islamist government, as sporadic clashes erupted nearby.
- [KHALED DESOUKI/AFP/Getty Images]

An Egyptian protester is carried away after being injured during a protest in Tahrir Square on January 25, 2013 in Cairo. Huge crowds are expected to demonstrate in Egypt on the second anniversary of the revolution that ousted Hosni Mubarak and brought in an Islamist government, as political tensions simmer and economic woes bite.
- [MOHAMMED ABED/AFP/Getty Images]

Egyptian security forces are seen through a hold in the wall, as they throw stones at protesters in Sheikh Rayhan street, that leads to the Interior Ministry headquarters, near Tahrir Square, on January 25, 2013. Thousands of Egyptians marched in Tahrir Square to demand change, two years after the uprising that ousted Hosni Mubarak and ushered in an Islamist government, as sporadic clashes erupted nearby.
- [KHALED DESOUKI/AFP/Getty Images]

Egyptians treat a wounded protester during clashes with riot police in Tahrir Square on January 25, 2013. Huge crowds are expected to demonstrate in Egypt on the second anniversary of the revolution that ousted Hosni Mubarak and brought in an Islamist government, as political tensions simmer and economic woes bite.
- [MOHAMMED ABED/AFP/Getty Images]