PARIS — President François Hollande of France said Tuesday that his Socialist government would do everything necessary to ensure that law and order prevailed after rioting overnight in the northern city of Amiens.


The rioting, which followed several days of minor clashes between young people and the police, erupted overnight, with cars and three buildings burned and 17 police officers injured by rocks, fireworks and buckshot, said a spokeswoman for the Somme Prefecture, which covers Amiens.


Mr. Hollande said he had sent his interior minister, Manuel Valls, to Amiens “to say there once again that the state will mobilize all its resources to combat this violence.”


“Our priority is security, which means that the next budget will include additional resources for the gendarmerie and the police,” Mr. Hollande said. “Security is not just a priority for us, but an obligation.”


As the first Socialist president in 17 years, Mr. Hollande has been eager to show that he is tough on security issues, which was one of the hallmarks of the former center-right president, Nicolas Sarkozy. Mr. Hollande spoke on Tuesday, his 100th day in office, from a southern town where he had interrupted his vacation to meet with the family of one of two policewomen who were killed while on duty in June. The suspect in the case is a recently released convict.


Mr. Hollande promised more beat officers during his campaign, and he was criticized this summer when Mr. Valls authorized the dismantling of encampments of Romanians and Bulgarians, most of them Roma, who have stayed longer than allowed in France.


Two summers ago, Mr. Sarkozy was much criticized for doing the same thing, but he argued that the camps were illegal and that France could not allow uncontrolled immigration. Romanians and Bulgarians, who are not part of the European Union’s Schengen agreement, which allows visa-free travel in 26 European nations, can come to France without a visa for only three months. After that they have to leave if they cannot show that they have obtained work or education visas. In general, those who agree to go home are flown back free and given about $370. Many then return to France.


The rioting in Amiens, if it continues or spreads, could represent a challenge to Mr. Hollande in a period of record joblessness and flat economic growth. Weeks of rioting in 2005, in the largely immigrant suburbs around Paris, led to a state of emergency and much soul-searching in France about integration, assimilation and the ghetto-like housing projects that ring the city.


Gilles Demailly, the Socialist mayor of Amiens, 75 miles north of Paris, told French journalists that “there have been regular incidents here, but it has been years since we’ve known a night as violent as this, with so much damage done.” He said tensions had been mounting in the area, where unemployment is high.


The clashes involved about 100 youths from a poor district in northern Amiens and up to 150 police officers, who used tear gas and rubber bullets. A nursery school was ransacked and partly burned, as was a community gym. But the police made no arrests.


The district, Fasset, is one of 15 special urban zones identified by the Hollande government that are supposed to get more policing next month.


Mr. Valls arrived on Tuesday for meetings with the mayor, the prefect and some residents of the neighborhood. Some residents booed him, while three police unions called on the government to show firmness and determination in response to the violence and the attacks on police officers.


Mr. Valls expressed concern for the neighborhood, but said at a news conference that order must be restored and that violence was unacceptable. “Shooting a police officer?” he asked. “Burning a school? And then questioning these forces? It’s intolerable.”


There had been a few days of “classic violence,” largely the setting of fires in garbage cans, said the prefecture spokeswoman, who in common with police practice did not give her name.


News reports said that many residents of the neighborhood were attending a wake for a local 20-year-old who died Thursday in a motorbike accident when the police arrested a man for dangerous driving. The arrest was seen as insensitive and led to minor clashes on Sunday. Monday’s clashes began when youths began confronting police officers who had been sent to provide more security.