CAIRO: Volleys of tear gas left a white cloud over Cairo's Tahrir Square and surrounding streets in the vicinity of Egypt's Interior Ministry, in the fourth day of clashes between security forces and rock-throwing youth protesting a deadly soccer riot.

Black-clad riot police fired rubber bullets from armored vehicles on Sunday to push protesters away from the ministry, while building walls of concrete on street entrances.

Since Thursday, 12 people have been killed in Cairo and Suez, a hotbed of anti-government protests to the east of the capital.

Egypt entered a new cycle of violence following riots Wednesday in the Suez Canal city of Port Said that left 74 dead.

Protesters accuse the security forces of deliberately failing to prevent the bloodshed.