The suspected Islamist militant held over an attack against a French chemical plant has admitted killing his boss, a source close to the investigation said on Sunday.

Yassin Salih, 35, told detectives he had killed Herve Cornara in a parking area before arriving at the plant in Saint Quentin-Fallavier, 30 km (20 miles) south of Lyon, where he attempted to cause an explosion on Friday.

Police found the 54-year-old victim's decapitated body at the scene of the attack, where there were no other casualties.