Paris, June 26 (RHC)-- In France, one person was found decapitated and two others wounded Friday after an assailant -- with a possible accomplice -- drove a vehicle onto an industrial complex near the French city of Lyon and tried to blow up a U.S.-owned gas factory.

"The intent was without doubt to cause an explosion. It was a terrorist attack," President Francois Hollande said at a news conference in Belgium. The attack targeted a chemical factory in the town of Saint-Quentin-Fallavier, about 20 miles southeast of Lyon in southeastern France. The plant is owned by the U.S. firm Air Products.

Witnesses said a man drove into the forecourt of the gas supply company and spun his car around in the yard, reports CBS News' Elaine Cobbe. Then they heard an explosion and saw fire.

The slain victim's head was found several meters away from the body, stuck on a perimeter fence, with Arabic writing on or near it. There were also flags or banners bearing Arabic writing found at the scene. The newspaper Le Dauphine Libere reports that the decapitated victim was the manager of a transport company who happened to be at the site for a delivery.

French Defense Minister Jean-Yves Le Drian declared the attack an "act of terrorism" and said the national Defense Council was to convene at the presidential Elysée Palace. Hollande cut short his visit to Brussels for a European Union summit and returned to Paris early Friday.