PARIS (AP) _ French police discovered a car Thursday on the southwestern edge of Paris containing materials that could be used to make explosives, and investigators were questioning the owner.

The car, found along the highway that circles Paris, contained a sack of nails, small bottles of butane gas, electric wire, batteries and unidentified powder and chemicals, police said. Authorities did not find a detonator.

The Paris prosecutor's office referred the case to the anti-terrorist brigade and investigators were questioning the car's owner, police said.

A French journalist at Liberation newspaper alerted police after receiving an anonymous phone call about the car. The caller claimed to belong to the Corsican separatist group Armata Corsa, which has threatened to carry out attacks on the French mainland.

Police said they did not immediately plan to step up security measures put in place in the capital since Armata Corsa's threats surfaced in early January.