Clichy-Sous-Bois, France ? Police deployed 4,000 reinforcements as marauding youths torched at least two public buses Friday, the one-year anniversary of the deaths of two teenagers that ignited weeks of riots in largely immigrant housing projects across France.

After the buses were burned, Paris’ transport authority curtailed bus service in the Seine-Saint-Denis region north of the capital, which is home to thousands of immigrants and their French-born children.

Thierre Ange, a 19-year-old witness, said four men attacked the bus, “made everyone get off, then they hit a woman and dragged out the bus driver by his tie” and torched the bus with a gasoline bomb in a bottle. The blackened carcass of another bus that was burned earlier stood across town in Le Blanc-Mesnil.

Flaming cars became a symbol of last year’s rioting, which jolted France into recognizing a failure to give equal opportunities to many minorities – especially those of Arab and black African origin – and the country’s 5 million-strong Muslim population.

The national police said 50 units of extra officers and riot police – or about 4,000 people – were deployed across the country to brace for a possible resurgence of violence. Some 7,000 police are at the ready on an average night in France, officials have said.

A policeman stands by the charred remains of public transport bus in Le Blanc-Mesnil, north of Paris. Youth gangs allegedly set the bus on fire Friday, which was the anniversary of two deaths that ignited weeks of riots in largely immigrant housing projects across France a year ago.

Dozens of police officers, wielding riot gear and backed by a helicopter, swept into a housing project in Montfermeil, a neighboring town to Clichy-sous-Bois.

Last year’s outburst of anger at the accidental deaths of the two teens – who were electrocuted in a power substation in Clichy-sous-Bois, northeast of Paris, while hiding from police on Oct. 27, 2005 – grew into a broader challenge of the French state.

Several hundred people marched silently Friday through Clichy-sous-Bois in honor of the two teens, Zyed Benna and Bouna Traore. Benna, 17, was buried in his father’s native Tunisia. Traore, 15, was of Mauritanian descent.

Clichy-sous-Bois has no police station, so officers patrolling here come from outside and have no connection to residents. There is no public transportation and few families own cars, leaving most people virtually trapped.

Unemployment among its 28,000 residents is 23.5 percent – well above the 9 percent national average – and is 32 percent for those between the ages of 15 and 24, according to the newspaper La Croix.