Two inmates in a French prison have been placed under formal investigation days before their expected release from jail on suspicion of plotting attacks, a judicial source said on Tuesday.
More than 240 people have been killed in France in attacks since 2015 by assailants who pledged allegiance to, or were inspired by, Islamic State, and France has a long record of radicalization in its prisons.
The two inmates were taken from their cells in the Fresnes prison, just south of Paris, and questioned over four days before being placed under investigation on charges of criminal association linked with terrorism plans, the source said.
Earlier this month, France's parliament adopted bill to bolster police surveillance powers against attacks and make it easier to close mosques suspected of preaching hatred. Civil rights groups warned it would lead to personal freedoms being infringed.
The two men, who were due to be released in the coming days after completing sentences for non-terrorist crimes, were known in jail for being radicalized, the source added.
French TV station LCI said the two were plotting attacks against jail wardens and police forces, while a source close to the probe said they also had other targets planned.
The two men were in phone contact with other radicalized inmates in other jails in France, the judicial source said.