Gangs of stone-throwing youths clashed with police and torched 180 cars overnight in several towns north and west of Paris in an escalation of dusk-to-dawn violence that has raged since last Thursday following the death of two teenagers in the north-east suburb of Clichy-sous-Bois.
Thirty-four people were arrested in the rampages, which have so shaken authorities that President Jacques Chirac came forward to call for calm and vow to investigate the teens' deaths.
"Tempers must calm down," a spokesman quoted him telling his cabinet. "A lack of dialogue and an escalation of disrespectful behaviour would lead to a dangerous situation," he said, adding that "there can be no area existing outside the law" in France.
Prime Minister Dominique de Villepin put off indefinitely a trip to Canada originally scheduled for Wednesday to call an emergency meeting of ministers to discuss the problem and attend a parliamentary session in which he called the violence "extremely serious".
He cautioned that there was "no miracle solution to the situation in this districts."
Interior Minister Nicolas Sarkozy cancelled a trip next week to Pakistan and Afghanistan to deal with the worsening situation.
In all, more than 80 people have been arrested and two dozen police hurt since the start of the riots last week. They were triggered by the accidental electrocution of two youths, aged 15 and 17, who had scaled an electrical relay station's walls to escape a police identity check in the street.