France is increasing security at Jewish and other religious sites after blank rounds were fired at a synagogue west of Paris amid renewed concerns about anti-Semitism across the country.

President François Hollande sought to allay tensions yesterday between Jews and Muslims aggravated by a series of violent incidents in recent months.

Mr Hollande singled out hateful extremists for criticism and urged respect for all religions in a country that is officially secular. Fr ance is home to Western Europe's lagest Jewish and Muslim communities. He said that "in the coming days, in the coming hours", authorities would increase security at religious sites to prevent the kind of attack at a synagogue in the Paris suburb of Argenteuil on Saturday night.

A synagogue representative said witnesses heard what sounded like a weapon being fired and that police said empty casings found at the scene indicated they were blanks. Local police would not comment on the incident.

Hours earlier police carried out raids across France targeting a suspected jihadist cell of young Frenchmen accused of links to a grenade attack on a kosher grocery store.