The heavy police presence appeared to have paid off, deterring the rioters from repeating their rampages of the previous week. Several cars were burnt and youths skirmished with police in four districts, but by midnight the scale of the incidents was far smaller than earlier in the week.

M de Villepin, whose centre-right Government has come under attack for mishandling the riots, issued his pledge before the Senate, saying: “The Republican State will not give in. Order and justice will be the final word in our country. A return to calm and the restoration of public order are our absolute top priority.”

Youths from the largely Muslim ghettos have stoned police, set fire to shops and offices, and burnt more than 300 vehicles since October 27.

Francis Masanet, leader of the UNSA police union, said: “It is very serious and we fear that events could get worse.”

Evidence of the scale of law-breaking, in what are officially known as “les quartiers difficiles”, came with a police report yesterday that 28,000 vehicles had been torched in outbreaks of urban violence in France so far this year.

On Wednesday night 40 cars and 2 buses were set alight, police and firefighters were pelted with projectiles in nine towns in Seine-Saint-Denis, the suburban département that has France’s highest concentration of crime, unemployment and poverty. Three firearm rounds, apparently from shotguns, were discharged at police and firemen, causing no injuries, the authorities said.

After rampaging youths attacked television crews and set fire to a broadcast van at Blanc-Mesnil, the national networks said that they would stay away from the scene because rioters were playing to the cameras.

M de Villepin’s tough warning was an attempt to put an end to an impression that a feud with Nicolas Sarkozy, the Interior Minister, had prevented the Government from getting a grip on the unrest. He had initially stayed silent as M Sarkozy inflamed passions with threats to clean the “scum” out of the rundown estates.

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