France is cracking down on terror after a sting operation in connection with an attack on a Jewish supermarket left one dead and 11 arrested.

French President Francois Hollande announced just prior to the start of the Jewish holidays of Shemini Atzeret and Simchat Torah that France would take steps to “fight all terror threats.”

The statement came following a “vast anti-terrorist operation” Saturday night in which police killed 33-year-old Jeremy-Lous Sidney, a convert to Islam in a raid in the northeastern city of Strasbourg, and arrested 11 other suspects linked to a radical Islamist terrorist cell. Hollande gave no details on the organization, but said the group had “struck in the past” and that officials had believed it “could stage attacks in the coming weeks.” The detainees were all in their 20s and 30s, according to Paris prosecutor Francoid Molins, who said that some were “common criminals who set out on a path of radicalization toward Islamist jihadism,” AFP reported.

Sidney’s fingerprints were found on the remains of the grenade used to bomb the Naouri Sarcelles kosher supermarket last month in Sarcelles (Val d’Oise). One person was slightly wounded in the attack. The city, a suburb of some 60,000 residents, is located north of Paris and is home to a flourishing Jewish community, sometimes referred to as “little Jerusalem.” 

Within hours of Sidney’s death, blank shots were fired at a synagogue in the Paris suburb of Argenteuil. Jewish leaders asked officials to beef up security around its neighborhoods, and services at the synagogue for Sukkot were canceled.

Richard Pasquier, President of the Representative Council of France’s Jewish Associations (CRIF), and Jewish central Consistory President Joel Mergui met with reporters together with the heads of France’s Jewish Associations at a news conference on the steps of the Elysee Palace, after their meeting with the French president.

Hollande also met with reporters at the palace and emphasized,“The state is totally mobilized to fight all terror threats…. planned anti-terror laws will be put before parliament as soon as possible,” according to AFP. 

The need for the legislation was underscored by French Interior Minister Manuel Valls, who warned in a radio interview of an increase in local radical Islamists. “There is a terrorist threat in France,” Valls acknowledged bluntly. “It does not appear to come from foreigners, it appears to be French converts.”