Reuters reports that unknown persons rammed a car into the premises of a US gas company in southeast France, exploding gas containers in an apparent attack which bore the hallmarks of Islamist militants and left one dead and several wounded, police sources and French media said.

French media said a decapitated head was found at the site, along with a flag bearing Islamist inscriptions. A police source said he could not confirm the decapitation but said it look as if it was the case. One suspect had been arrested. ,

"The intent was without doubt to cause an explosion. It was a terrorist attack," Mr Hollande told reporters as he cut short his stay at a European summit in Brussels