French President Jacques Chirac addressed the public Sunday for the first time in 11 days of the country's worst violence in decades, saying his government's "absolute priority" was "reestablishing security and public order." His brief appearance came hours after the arson rampages struck the heart of Paris and accelerated their spread to other major French cities.

Those sowing "violence or fear" will be "arrested, judged and punished," Chirac said from the steps of the Elysee Palace after an emergency meeting of his national security council.

Law enforcement officials said the unrest -- including nightly arson and what they described as copycat attacks -- was spreading more rapidly than their ability to respond to it. The violence began in the northern suburbs of Paris, where large populations of immigrants and their French-born children live.

Police said gangs of youths, apparently roused by television images and summoned by Internet blogs, torched 51 cars in Paris on Saturday night, including in attacks at the congested Place de la Republique near the trendy Marais district. Blazes were also set in 42 cities from Rennes, the capital of Brittany in the north, to Nice on the Cote d'Azur in the south. Details from each day's violence are not fully known until the next morning.

"What do you expect?" said Paul Merault, a police spokesman interviewed by telephone in the southwestern city of Toulouse, where bands of youths set fire to 50 cars Saturday night. "For the last 10 days these kids have been watching TV, and naturally there is a copycat effect, a desire to imitate what they see on the screen."

The violence continued Sunday night with more arson attacks across the country and rioters shooting at police in the suburb of Grigny, south of Paris. Ten police officers were injured, two of them seriously, according to early reports.

Violence is now erupting in towns with little history of unrest, underscoring the widespread dissatisfaction with the government's policies toward its poorest citizens.

"If we don't take the appropriate measures right away, things could get way out of proportion," said Stephane Ribou, a police spokesman in Rennes. Ribou said the city of 200,000 had one of the lowest delinquency rates in the country. On Saturday night, roving groups of young men set 18 cars and 40 garbage bins ablaze there, he said.

In one of the most extreme episodes of violence Saturday night, youths in Evreux, a city in northwestern France, assaulted police and set fire to a strip mall, two schools, a post office and 53 cars.

"Rioters attacked us with baseball bats," Philippe Jofres, a deputy fire chief, told France-2 television. "We were attacked with pickaxes. It was war."

Five police officers and three firefighters were injured in the clashes, police said.

In Corbeil-Essonnes, a suburb south of Paris, a car rammed into a McDonald's restaurant, setting it ablaze and burning it to the ground. And Justice Ministry officials said they discovered a crude bomb-making workshop in a dilapidated building in Evry, south of Paris, that contained 100 empty bottles and gallons of fuel, according to the Associated Press.

Throughout the Paris suburbs, arsonists hit gymnasiums, schools and other symbols of the government.

Nationwide, 1,295 cars were burned Saturday night, according to Patrick Hamon, a spokesman for the national police. He said police detained 349 people, though local police agencies said they released many of the youths they picked up during the night.

The riots followed the deaths of two teenagers from the northern suburbs of Paris who were electrocuted in a power substation where they were trying to dodge a police checkpoint. The youths' families said the two were frightened by police who were chasing them; police deny they were pursing the teenagers. The incident incensed youths in the neighborhoods, where unemployment is high, particularly among the French-born descendants of Muslim Africans and Arabs who say they feel the government has abandoned them.

The tensions have been exacerbated by comments from Interior Minister Nicolas Sarkozy, whose references to the rioters as "scum" prompted youths participating in the violence to demand his resignation. Sarkozy has been considered a likely contender in the 2007 presidential election.

As the violence leapt this weekend from the troubled suburbs of Paris into the heart of the capital and to other major cities and popular tourist destinations, foreign embassies issued travel advisories.

The U.S. Embassy warned travelers against taking trains from Paris to Charles de Gaulle International Airport because of attacks on two trains last week. The Russian Embassy established a hotline for tourists after a bus carrying Russian visitors was set afire by youths last week. No one on the bus was injured, according to news reports. The Canadian Embassy said citizens "should be extremely careful" if they have to travel through the affected areas. Britain also has issued warnings.

Most nightly bus services north and east of Paris were suspended Saturday because of the large number of attacks on transit buses.

French officials and local residents have expressed concern that the media images of blazes and rioting could damage tourism in the country, which attracts 75 million visitors a year.

"You are walking around in a beautiful place, but you read in the newspapers that the suburbs were burning last night," said Paolo Soler, 57, a Spanish real estate agent who was visiting Paris with his wife on their wedding anniversary. "It's definitely a shock when you hear what's happening not so far from where you are staying."

Researchers Gretchen Hoff and Maria Gabriella Bonetti contributed to this report.

Smoke rises from the charred shells of buildings in a commercial center targeted by arsonists in Evreux, 60 miles west of Paris. Police said fires were set in 43 cities across the country, including central Paris, on Saturday night.