France's foreign ministry said a video of a French man kidnapped in Algeria was genuine."We confirm the authenticity of the video showing images of French hostage Herve Gourdel, kidnapped in Algeria in the region of Tizi Ozou on Sunday," the ministry said in a statement."The threats made by this terrorist group shows once again the extreme cruelty of Daech (ISIS) and those who say are affiliated to it."The Algeria-based Caliphate Soldiers, which on Sept. 14 pledged allegiance to ISIS, said on Monday it had taken Gourdel and would kill him within 24 hours if France did not stop its intervention in Iraq.