French police have extended the detention of a dozen suspected radical Islamists after finding bomb-making materials and weapons stashed in a garage near Paris.
French prosecutor Francois Molins described "particularly significant developments" into a police investigation of a suspected terrorist cell.
Molins says police found bomb-making materials and firearms at a garage in the Paris suburb of Torcy. He says police would keep suspected Islamist radicals in custody for another 24 hours.
Molins says authorities were confronted by an extremely dangerous terrorist cell. He says everything must be done to thwart the risk of a terrorist attack in France.
The suspects were rounded up last Saturday during a country-wide operation. Police shot dead another suspected Islamist, Jeremie Sidney, after he fired at them during a raid in the eastern city of Strasbourg.
Police have tied Sidney to a September grenade attack at a Jewish supermarket near Paris. Police say they have found a list of Jewish institutions during searches of the suspects' homes.
Fears of reprisals by radical Islamists have grown following the September publication of a crude video and French cartoons mocking the prophet Muhammad.
France's Jewish community, Europe's largest, is on edge. Earlier this year, self-proclaimed Islamist Mohamed Merah shot dead four Jews in the southern city of Toulouse.
For its part, France's Muslim community, which is also the largest in western Europe, is worried it may be unfairly stigmatized. President Francois Hollande has sought to calm the fears of both religious communities.