Authorities in France said Saturday that 129 people were killed and 352 injured Friday in the string of terrorist attacks that rocked Paris and sent shockwaves of grief across the globe.
At least six crowded sites including a concert hall, an avenue packed with cafes and the area around a national soccer stadium were targeted in the apparently choreographed gun attacks and bombings.
Before the smoke had settled Friday, President Hollande vowed to lead a "merciless" war against those responsible.
On Saturday, it emerged that ISIS had taken responsibility for the attacks in a statement circulated on social media by Islamic State supporters.
Six attackers blew themselves up at some point after the attacks. A seventh was shot by French authorities.
As part of the chaotic attack, gunmen armed with AK-47s attacked a restaurant near Paris' Bataclan concert hall on Friday night, and are believed to be on the loose.
Julien Pearce, a witness inside the concert hall, told CNN that masked gunmen fired randomly at concertgoers for 10 minutes. They were "very calm and very determined" as they silently shot at people, who were desperately trying to crawl to safety, he said.
As he left, he passed 20 or 25 bodies on the ground. While he was able to escape, some of his friends have messaged him to say they are still hiding inside.
"It was horrible," he said. "It was a bloodbath."
He said gunmen began firing on the crowd near the end of the concert, while the band was still on stage. "They were all dressed in black," he said.