More than 30 police were hurt by shots and rocks in Paris as unrest shook France for the 11th successive night.
Riot squad officers were injured as gangs armed with guns and baseball bats confronted police in suburbs south of Paris. Two were admitted to hospital with serious wounds.
The incidents came hours after President Jacques Chirac vowed to restore public order.
On the outskirts of several other major cities officers were targeted by gangs roaming low-income neighbourhoods and setting fire to scores of vehicles and properties.
The violence - the worst the country has seen since 1968 student revolts - continued despite increasingly tough reactions from police, who have arrested more than 800 people since the troubles began.
The Chirac Government has come under increased pressure to halt the riots, sparked by frustration among ethnic minorities over racism, unemployment, police treatment and their marginal place in French society.
"The Republic is quite determined, by definition, to be stronger than those who want to sow violence or fear," Mr Chirac said after chairing an emergency meeting with key ministers.
"They will be arrested, judged and punished," he promised.
In the western city of Rouen, a car was used as a battering ram against a police station, and in Toulouse, in the south, police had to fire tear gas grenades to push back a mob carrying baseball bats and throwing stones and bottles.
"These individuals seem to be looking for contact with police, and they are attacking us, unlike during the other nights," a senior officer said.
Arsonists also set fire to cars and rubbish cans in the cities of Nantes, Orleans and Rennes.
The new edge to the violence confirmed the riots were worsening, adding to a weekend that took the unrest to new heights with hundreds of vehicles burned and up to 200 localities affected.
So far, more than 3500 vehicles have been torched and schools and businesses set alight.
Prime Minister Dominique de Villepin said more police would be deployed, declaring: "We will not accept any lawless zone".
The extent of the unrest was brought home when 51 cars were petrol-bombed in the heart of Paris - the first time the centre of the capital had suffered significant attacks.
A police chief, Frederic Aureal, said his officers were encountering unprecedented hostility from gangs, which he described as "prepared, structured, armed".
"We have come face-to-face with people who have attacked us with picks, petanque balls, many Molotov cocktails," he said.
So far, no one has been killed in the unrest, which began on October 27 following the electrocution deaths of two teenagers who hid in an electrical substation in northeastern Paris to escape a police identity check.
One night out rioting
* 34 police injured.
* 528 vehicles torched.
* 95 arrests.
- AAP, Reuters
Unrest across France takes on sinister new edge
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