While mayors of riot-hit towns welcomed the tougher line, some asked what another measure announced by Villepin - extended powers for them - would actually mean in practice.

"Every time they announce more powers for mayors, they cut the funds," complained Jean-Christophe Lagarde, mayor of the north-eastern Paris suburb of Drancy.

Elisabeth Guigou, a Socialist deputy from the north-eastern Paris suburbs, said that invoking a curfew law passed during the Algerian war was "not the best reference" for fighting unrest among youths mostly of North African Arab and African origin.

The left-wing daily Liberation recalled Jacques Chirac was elected president in 1995 pledging to repair France's "social fracture" and his government was now imposing curfews. "Chirac's reign is a tragic farce," it wrote in an editorial.

The Interior Ministry said 814 vehicles had been torched by early Tuesday morning, compared to 1,408 for the whole previous night. It said it would give full figures later on Tuesday.

The number of injured police officers dropped from 36 on Sunday night to four overnight. Some 143 rioters were detained.

Villepin said 1,500 police and gendarmes would be brought in to back up the 8,000 officers already deployed in areas hit by unrest. He also promised to accelerate urban renewal programmes.

Government spokesman Jean-Francois Cope said: "The absolute priority is to show everyone that public authority must be re-established."

But Villepin dismissed growing calls for army intervention, saying: "We have not reached that point."

The opposition Socialists said Villepin had not done enough to give hope to those people in areas hit by the unrest, which has involved poor whites as well as French-born citizens of Arab or African origin complaining of racism and unemployment.

"Beyond the necessary calls for order, what was missing in the prime minister's address was a social dimension, a message and precise commitments towards the people of these areas in difficulty," the Socialist Party said in a statement.