Prime Minister Manuel Valls warned Saturday that France faced more attacks to come after a grisly killing in which a suspected extremist pinned the severed head of his boss to the gates of a gas factory.

Prime Minister Manuel Valls warned Saturday that France faced more attacks to come after a grisly killing in which a suspected extremist pinned the severed head of his boss to the gates of a gas factory.

The alleged assailant, identified as 35-year-old married father-of-three Yassin Salhi, also caused an explosion by smashing his vehicle into the Air Products factory near France's second city of Lyon.

The grisly killing came on the same day as two other attacks claimed by the Takfiri group, ISIL, which left 38 people dead at a beach resort in Tunisia and 27 in a suicide bombing in Kuwait.

The victim, a 54-year-old local businessman, was found with Arabic inscriptions scrawled on him and extremist flags were also found on the site at the small town of Saint-Quentin-Fallavier, some 40 kilometers from Lyon.

His head was "hung onto the fence surrounded by two Islamic flags bearing the Shahada, the profession of (the Muslim) faith," said French prosecutor Francois Molins.

Valls said Friday's attack would create tension in France -- home to Western Europe's largest Muslim population -- that "will be exploited".

"It's difficult for a society to live for years under the threat of attack," he told AFP on a flight back from Bogota, adding: "The question is not... if there will be another attack, but when."

This is the first time someone in France has been found beheaded by a suspected extremist, a method of killing that has become a trademark of the ISIL in Iraq and Syria.