Jews, Muslims and Christians marched in silent protest through a Lille cemetery Monday after vandals damaged dozens of Jewish gravestones, an incident that drew a high-level outcry and renewed fears of anti-Semitism at the start of Pessah. In Monday's ceremony in the northern city of Lille, about 1,000 people circled the damaged section of the Lille-Sud cemetery after a rabbi read a prayer. The group included local officials, representatives from religious groups and schoolchildren. More than 50 gravestones were knocked over or damaged in the attack overnight Saturday to Sunday. It was not clear whether it was linked to Pessah, which started Monday. The incident renewed concern about anti-Semitism in France, home to western Europe's largest Jewish population, and prompted a stern response from France's political, religious and human rights leaders. Among the most vocal were President Jacques Chirac and candidates to replace him in elections starting April 22. France's Human Rights League said in a statement Monday that the incident "showed the persistence of anti-Semitism in our country" and accused officials of failing to fight hard enough against it. The rector of the Paris Mosque, Dalil Boubakeur, called the incident "deeply execrable manifestations of racism and anti-Semitism." "That which hurts our brothers hurts us all," said the bishop of Lille, Monsignor Gerard Defois. The rabbi for Lille's Jewish community, Elie Dahan, said, "The community is injured but we are not afraid. We have passed through darker times." The city prosecutor put 40 investigators on the case. France sees occasional but persistent attacks against synagogues and Jewish schools and cemeteries. Concerns about France's relations with its Jewish population mounted last year after the brutal killing of a young Jewish man that authorities said might have been was linked to anti-Semitism. The latest incident came amid heated debate over France's "national identity," driven by conservative presidential front-runner Nicolas Sarkozy. The former interior minister - whose job included overseeing France's religious life - called recently for a ministry for immigration and national identity. Critics say the idea is racist. One of France's most respected figures, Auschwitz survivor and longtime politician Simone Veil, spoke out Monday against the idea - even though she recently joined Sarkozy's campaign team. "It's more than carelessness. It's more serious," she said in an interview published in the Jewish Tribune newspaper. Some have called Sarkozy's proposal a bid to poach votes from far right leader Jean-Marie Le Pen, who has been convicted of racism and anti-Semitism and embarrassed France by making it to second place in the last presidential elections in 2002. Le Pen, too, condemned the weekend vandalism, and suggested it was linked to the elections. He is currently polling fourth in the race.