The protesters were facing off with riot police for a second day. Authorities used water canon and tear gas to break up a protest Monday.

Police said nine officers were injured Tuesday, and 10 a day earlier.

Violence broke out when police, acting on a judge's order, arrived to raze shacks, some of which were built illegally on a football pitch in the working class El Madania neighborhood.

Youths in the neighboring housing project of Diar Chems fought off police attempts to take over the area, which lies about two kilometers (about a mile) from the North African nation's presidential palace.

Young men, many with their faces masked, threw things at police squads as they tried to enter the housing project. Women on their balconies supported the rioters with cries of "God is Great."

Residents said they were demonstrating for better housing, more jobs, a better lifestyle and the release of people arrested in Monday's violence.

"Not only have police not released the youth detained yesterday, but they tried to arrest more people this afternoon," said Ali Ramdane, a local resident. He blamed authorities for "stoking the fire."

Large numbers of unemployed young people in the streets often make Algiers restive, but the massive security presence usually prevents violence from erupting. Riots occur sporadically in the rest of the country.