A group of Islamic radicals have been charged with planning to kidnap a French judge.

Prosecutor Francois Molins said the Forsane Alizza group, or Knights of Pride, did physical training in parks and forests, collected weapons and preached hate and violence on their website, showing clips of Osama bin Laden.

The site was shut down after authorities banned the group in March.

Mr Molins said the investigation showed the network was organised around leader Mohammed Achamlane.

He stressed the group had no link to the killing spree last month in Toulouse that left seven dead. Suspected gunman Mohamed Merah was killed in a police stand-off.

The 13 – among 17 suspects detained in police raids last week – faced preliminary charges of criminal association linked to a terrorist network, a sweeping charge with a maximum 10-year prison term that is used in France to ensure a full investigation of terror suspects. Nine are being held in jail. The remaining four were released.

The prosecutor said several terror plans appeared to be in the works, including the kidnapping of a judge in Lyon. An official close to the investigation said the targeted judge is Jewish.

The magistrate in question has been placed under police protection.