PARIS - Masked youths clad in black set cars afire, smashed storefronts, and threw up roadblocks Tuesday, clashing with riot police across France as protests over raising the retirement age to 62 took a radical turn.
Hundreds of flights were canceled and desperate drivers searched for gas as oil-refinery strikes and blockages emptied the pumps at nearly a third of France's gas stations.
A series of nationwide protests against the bill since early September have been largely peaceful. But Tuesday's clashes, notably just outside Paris and in the southeastern city of Lyon, revived memories of student unrest in 2006 that forced the government to abandon another highly unpopular labor bill.
Still, President Nicolas Sarkozy was unbending, vowing to guarantee public order in the face of "troublemakers." The government announced a plan to pool gasoline stocks so that dry stations could be filled.
"There are people who want to work, the immense majority, and they cannot be deprived of gasoline," Sarkozy said.
A new test could come as early as Thursday, when students plan a day of mobilization with a demonstration in Paris hours before the Senate is to vote on the retirement measure.
Prime Minister Francois Fillon said after meeting with oil industry executives: "The government will continue to dislodge protesters blocking the fuel depots. . . . No one has the right to take hostage an entire country, its economy, and its jobs."
About 4,000 gas stations - out of 12,700 nationwide - were empty of gas Tuesday afternoon, the Environment Ministry said.
Half of flights Tuesday out of Paris' Orly airport, and 30 percent out of other French airports, were canceled, the DGAC civil aviation authority said. Flights were expected to be normal Wednesday.
French unions have a long tradition of street protests, but the current strife is particularly worrisome because it has touched the vital energy sector and is drawing often volatile youth into the mix.
Troublemakers tagged onto the coattails of student demonstrators in 2006 when the government was forced to abandon a law that made it easier for employers to hire and fire young people. And the specter of 2005 riots that spread through poor housing projects nationwide with large disenfranchised immigrant populations is never far away.
Today's protesters are trying to stop lawmakers from approving a bill that would raise the retirement age from 60 to 62, to prevent the pension system from going bankrupt as citizens live longer and a diminishing pool of young workers pay into the system.
Unions contend that the move would erode France's near-sacred tradition of generous social benefits - including long vacations, contracts that make it difficult for employers to lay off workers, and a state-subsidized health-care system - in favor of "American-style capitalism."
Some 1.1 million people joined 260 protest marches Tuesday across France, according to the Interior Ministry, though trade unions put the figure at three times that.
The Paris march, which drew 60,000 people according to police, was peaceful despite a morning of violence at a high school on Nanterre, just west of the French capital, where several hundred youths threw stones at police and scuffled with outsiders. Police, lobbing tear gas, charged and barricaded the area. An Associated Press photographer was knocked off his motorbike and punched by the youths.
The most violent clashes occurred in Lyon, where rampaging youth torched garbage cans and cars. Numerous shops were pillaged.
Sarkozy has long touted his plan to increase the retirement age as his priority reform ahead of 2012 presidential elections, and the measure is expected to pass easily in the Senate, after being approved earlier by the lower house of parliament. But the unpopular measure is widely seen as feeding Sarkozy's dismal approval ratings.
His detractors contend that the retirement measure favors the rich. Sarkozy calls the change his "duty" as head of state. The protests come as countries across Europe are cutting spending and raising taxes to bring down record deficits and debts.