French President Francois Hollande vowed to attack the terrorist IS group without mercy as it admitted responsibility Saturday for orchestrating the deadliest attacks inflicted on France since World War II, AP reported. Hollande said at least 127 people died Friday night in shootings at Paris cafes, suicide bombings near France's national stadium and a hostage-taking slaughter inside a concert hall. Hollande, who declared three days of national mourning and raised the nation's security to its highest level, called the carnage "an act of war that was prepared, organized, planned from abroad with internal help." The terrorist IS group's claim of responsibility appeared in Arabic and French in an online statement circulated by the terrorist IS supporters.