Youths Torch Buses Around Paris.

Youths forced passengers off three buses and set them on fire overnight in suburban Paris, raising tensions Thursday ahead of the first anniversary of the riots that engulfed France’s rundown, heavily immigrant neighborhoods.

No injuries were reported, but worried bus drivers refused to enter some suburbs after dark, and the prime minister urged a swift, stern response.

The riots in October 2005 raged through housing projects in suburbs nationwide, springing in part from anger over entrenched discrimination against immigrants and their French-born children, many of them Muslims from former French colonies in Africa. Despite an influx of funds and promises, disenchantment still thrives in those communities.

About 10 attackers - five of them with handguns - stormed a bus in Montreuil east of Paris early Thursday and forced the passengers off, the RATP transport authority said. They then drove off and set the bus on fire.

Late Wednesday, three attackers forced passengers off another bus in Athis-Mons, south of Paris, and tossed a Molotov cocktail inside, police officials said. The driver managed to put out the fire. Elsewhere, between six and 10 youths herded passengers off a bus in the western suburb of Nanterre late Wednesday and set it alight.