French official says Islamist radicals detained last week were planning to kidnap a Jewish magistrate, AP reported.

Preliminary charges are being filed against the members of the banned group, Forsane Alizza, on Tuesday, April 3 for criminal association with a terrorist enterprise.

That means an investigating magistrate has strong reason to believe a crime was committed but allows more time for investigation.

The official, who is close to the investigation, spoke on condition of anonymity, citing policy.

Friday's raids netted more than a dozen people in sweeps around the country.

The head of France's counterespionage agency has said the group is not linked to the 23-year-old Frenchman who police say claimed responsibility for a killing spree in southwestern France last month.