More than 1 million people poured into the streets across France and strikers disrupted air, rail and bus travel Tuesday �� even shutting down the Eiffel Tower �� in the largest nationwide protest over a youth labor law.

Scattered violence erupted in Paris, and riot police used water cannons and tear gas to disperse several thousand youths who pelted them with stones and bottles after an otherwise peaceful march. More than 240 people were arrested.

Unions and the leftist opposition joined in solidarity with the angry students for the one-day strike, increasing the pressure on Prime Minister Dominique de Villepin to withdraw the measure that makes it easier to fire young workers.

Although Villepin held firm, cracks opened in his conservative government. Interior Minister Nicolas Sarkozy, in a clear break with Villepin, suggested suspending the law to allow for negotiations. (On Deadline: France is in turmoil)

With the government in crisis, President Jacques Chirac canceled a trip planned for later in the week to stay in Paris.

Police and organizers' estimates for the number of marchers varied greatly, but both showed that the protest movement is growing in strength.

Police said 1,055,000 people took part in more than 250 protests nationwide, including 92,000 in Paris. The organizers' total was closer to 3 million, with 700,000 at the march from the Left Bank to the heavily policed Place de Republique.

Elsewhere, 31,000 marched in the southwestern city of Bordeaux, 28,000 in the southern port of Marseille, 26,000 in the Alpine city of Grenoble, 17,000 in Lyon and hundreds of thousands in dozens of other cities and towns, according to police.

The nationwide strike �� the first time that unions had ordered walkouts in solidarity with students spearheading the protests �� slowed train, plane, subway and bus services to a fraction of their normal levels.

The Eiffel Tower was closed, its employees said. Some elementary and high schools also were shut as teachers walked off the job.

National newspapers were not on sale at newsstands, and radio and television broadcasts were limited.

The State Department advised Americans in France to avoid areas where crowds were expected to gather and to exercise caution, particularly at night.

"We are here for our children. We are very worried about what will happen to them," said Philippe Decrulle, an Air France flight attendant at the Paris protest. "My son is 23, and he has no job. That is normal in France."

Source: Agencies