PARIS, France (CNN) -- French suburbs stayed relatively calm Wednesday night after 1,000 riot police were deployed to quell disturbances that began when two teenagers died in a collision with a police car, French officials said.
Riot officers patrol the streets of Paris on Wednesday night.
Wednesday was the fourth night of unrest that on prior nights resulted in violent clashes between angry youths and police, and the burning of buildings and cars from the Paris suburbs to the southern city of Toulouse.
No injuries to police were reported, Laurente Wittek, a spokeswoman for the Interior Ministry, told CNN. She said Thursday that there had been a "clear reduction" in the rioting.
Meanwhile, French President Nicolas Sarkozy vowed to punish those responsible for shooting at police. Sarkozy met Wednesday with the families of the youths on the motorcycle who were killed.
The worst bouts of violence were Monday and Tuesday nights, when police made arrests in the northern Paris suburb of Villiers-le-Bel, where the collision occurred.
In Toulouse, 20 cars were burned and rioters set fire to two libraries on Tuesday.
"There were some problems but we can say that it was much better than previous days," Wittek said.
Sunday and Monday, rioters bombarded police with Molotov cocktails, baseball bats and bottles filled with acid, as the violence spread from Villiers-le-Bel to nearby towns.
Police in the Val D'Oise prefecture north of Paris said several officers were injured during the week. Three were hospitalized, including one with a serious eye injury.
French media reported that some rioters shot at police.
Sarkozy promised to catch the perpetrators of what he called "an attempted murder."
"So that things are very clear: what has happened is absolutely unacceptable. Those who shoot at civil servants will be brought to account before justice," he said on French television Wednesday.
Sarkozy, who caused controversy two years ago when he referred to rioters in Paris as "scum," struck a more conciliatory tone, meeting with the parents of 15- and 16-year-old boys killed Sunday evening, Wittek said.
The pair died when their motorcycle hit a patrol car in Villiers-le-Bel, police said. Police contend the teenagers, who were riding an unregistered cycle and not wearing helmets, drove through a red light.
Some residents in the town accused police of fleeing the scene without helping the boys, who were the sons of African immigrants.
The prosecutor's office in the nearby town of Pontoise has begun an inquiry into Sunday's deaths. Watch as fires burn, police respond »
The newspaper Le Figaro, citing initial findings from a police watchdog group investigating the incident, said the boys' motorbike was driving "at very high speed" and had failed to yield the right-of-way the police patrol vehicle.
The police car was moving safely within the speed limit -- about 25 mph (40 km/h), the newspaper reported, quoting the investigators.
In November 2005, violent protests over at least three weeks prompted the government to declare a state of emergency.
The violence began after the deaths of two young men of North African descent who were electrocuted when they hid in an electrical substation, because they believed police were chasing them. Watch how authorities are dealing with the unrest »
Young people in poorer neighborhoods -- many populated largely by immigrants and their French-born children -- began rioting and burning cars in an eruption of their frustration at the problems of unemployment and discrimination.
Villiers-le-Bel was not affected by that violence. E-mail to a friend
--CNN's Niki Cook in Paris contributed to this report.