Egyptian security forces have clashed with protesters in Cairo's Tahrir Square in a continued effort to disperse those calling for the ruling military council to step down.

Police and soldiers raided the square early Tuesday trying to clear the area in the center of the capital that served as the hub of protests against former leader Hosni Mubarak.

Protesters and security forces hurled stones at each other, and police fired shots to try to disperse the demonstrators as the clashes stretched into a fifth day.

At least 12 people have been killed and more than 500 others have been hurt since Friday.

Egypt's military rulers have defended the use of force, saying the protesters have been provoking soldiers and destroying government property.

U.S. Secretary of State Hillary Clinton said in a speech late Monday that the recent events in Egypt are “shocking,” particularly the treatment of women.

“Women protesters have been rounded up and subjected to horrific abuse,” said Clinton. “Journalists have been sexually assaulted. And now, women are being attacked, stripped, and beaten in the streets. This systematic degradation of Egyptian women dishonors the revolution, disgraces the state and its uniform, and is not worthy of a great people.”

Clinton said the military rulers and major political parties are keeping women out of the decision-making process as Egypt continues its political transition.

The protesters are demanding the military rulers step down immediately and hand power to a civilian government. They accuse the military council of manipulating the country's transition process to retain permanent powers.