"It's an act of war committed by a terrorist army, Daech (Islamic State), a jihadist army," French President Francois Hollande said on Saturday.
"It is an act of war prepared, organized, planned from outside and with internal complicities that the investigation will confirm," Hollande said. "It is an act of absolute barbarism," Xinhua quoted him as saying.
Given the severity of the Friday night terror attacks in Paris that left 127 people dead, Hollande announced a three-days national mourning.
"The country is in sorrow, I made a decree to extend the national mourning for three days. Under the state of emergency, the police and army are mobilized, and I salute their courage," he said.
The president assured that "all security measures" will be taken.