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.

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.