PARIS -- French police are hunting possible accomplices of eight assailants who terrorized Paris concert-goers, cafe diners and soccer fans in this country's deadliest peacetime attacks, a succession of explosions and shootings that cast a dark shadow over this luminous tourist destination.
Parisians who went to sleep in horror at initial news of the attacks woke Saturday to learn that at least 127 people were killed and scores wounded. World leaders joined together in sympathy and indignation, New York police increased security measures, and people around the world reached out to friends and loved ones in France.
Speaking to his grief and shock-stricken nation Saturday morning, President Francois Hollande said the attacks were "an act of war" carried out by the Islamic State of Iraq and Syria (ISIS), which planned the coordinated assault outside the country but worked with people in France.
ISIS also claimed responsibility for the attack in a statement, calling it a "blessed invasion" of Paris.
Islamic extremists are angry at France's military operations against ISIS and al Qaeda affiliates, who targeted satirical newspaper Charlie Hebdo this year and have hit Jewish and other sites in France in the past.
CBS News contributor Mike Morell, a former deputy director of the CIA, told Scott Pelley on Friday night the attack was clearly well-coordinated.
"We're talking about a large group of them. We're talking about multiple simultaneous attacks, and they kept it secret; that is a very difficult thing to do," Morell said. "It requires operational sophistication. We haven't seen that level of sophistication since the London bombings."
Morell noted that ISIS "has been working on a capability to conduct attacks in Western Europe" -- a capability already proven by al Qaeda's Yemen franchise, AQAP, with the attack on Charlie Hebdo.
Hollande convened a special security meeting Saturday morning. He vowed to be "merciless" with the nation's foes following what he called unprecedented terrorist attacks.
In a new development for France, seven attackers died in suicide bombings, the Paris prosecutor's office said. Another was killed by police, and prosecutor's office spokeswoman Agnes Thibault-Lecuivre said authorities couldn't rule out that other attackers were still at large. Investigators were also looking for possible accomplices.
The attacks, on at least six sites, were near-simultaneous.
Three suicide bombs targeted spots around the national stadium Stade de France, north of the capital, where the French president was watching an exhibition soccer match between the French and German national teams.
Then gunshots overpowered the clinking of wine glasses in a trendy Paris neighborhood. Blood hit the pavement after gunmen targeted a string of popular cafes, crowded on the unusually balmy Friday night, and about 37 people were killed, according to Paris Prosecutor Francois Molins.
The attackers then stormed a concert hall, the Bataclan, hosting an American rock band, opened fire on the panicked audience, then took them hostage. As police closed in, three detonated explosive belts, killing themselves, according to Paris police chief Michel Cadot.
Another attacker detonated a suicide bomb on Boulevard Voltaire, near the music hall, the prosecutor's office said.
The Bataclan was the scene of the worst carnage. More than 80 people were reportedly killed in the venue alone, according to Parisian officials.
Zsuzsa Kövér narrowly escaped the hostage taking at the Bataclan, thanks in part, she said, to her boyfriend's knowledge of the venue as he used to work there.
Kövér told CBSN's Vladimir Duthiers and Anna Werner she and her boyfriend were in the balcony of the Bataclan when they started hearing gunshots.
"Between two songs, we just hear this shooting going on," she said. "But first, we don't know if it's shooting -- that's not something you expect on a gig. So we were just trying to figure out what was happening, and then we just see that everyone is laying on the floor downstairs."
Kövér wasn't able to see the attackers, but her boyfriend saw a man armed with a machine gun. She said it took them about ten minutes to get out of the building.
"I'm incredibly lucky and I'm really grateful, especially to my boyfriend, who worked there before," Kövér said. "He actually advised, like, which way to go and which exit we should take, so that was really good. We stayed really focused. But... it's a huge shock. And if I just think of what could have happened, if we had been separated or we could not get out, I don't really want to think about it at the moment."
Sylvain, a tall, sturdy 38-year-old concert-goer, collapsed in tears as he recounted the attack, the chaos, and his escape during a lull in gunfire.
"I was watching the concert in the pit, in the midst of the mass of the audience. First I heard explosions, and I thought it was firecrackers.
"Very soon I smelled powder, and I understood what was happening. There were shots everywhere, in waves. I lay down on the floor. I saw at least two shooters, but I heard others talk. They cried, 'It's Hollande's fault.' I heard one of the shooters shout, 'Allahu Akbar,'" Sylvian told The Associated Press. He spoke on condition that his full name not be used out of concern for his safety.
He was among dozens of survivors offered counseling and blankets in a municipal building set up as a crisis center.
Jihadis on Twitter immediately praised the attackers and criticized France's military operations against ISIS extremists.
Hollande declared a state of emergency and announced renewed border checks along frontiers that are normally open under Europe's free-travel zone.
"A determined France, a united France, a France that joins together and a France that will not allow itself to be staggered even if today, there is infinite emotion faced with this disaster, this tragedy, which is an abomination, because it is barbarism," Hollande said.
President Obama, speaking to reporters in Washington, decried an "attack on all humanity," calling the Paris violence an "outrageous attempt to terrorize innocent civilians."
A U.S. official briefed by the Justice Department says intelligence officials were not aware of any threats before Friday's attacks.
The violence raises questions about security for the millions of tourists who come to Paris -- and for world events the French capital routinely hosts.
Some 80 heads of state, including possibly Mr. Obama, are expected for a critical climate summit in two weeks. In June, France is to host the European soccer championship -- with the Stade de France a major venue.
And Paris-based UNESCO is expecting world leaders Monday for a forum about overcoming extremism. Iranian President Hassan Rouhani canceled a trip because of Friday's attacks. Hollande canceled a planned trip to this weekend's G-20 summit in Turkey.
France has been on edge since January, when Islamic extremists attacked the satirical newspaper Charlie Hebdo, which had run cartoons of the Prophet Muhammad, and a kosher grocery. This time, they targeted young people enjoying a rock concert and ordinary city residents enjoying a Friday night out.
France has seen several smaller-scale attacks or attempts this year, including an incident on a high-speed train in August in which American travelers thwarted an attempted attack by a heavily armed man.
French authorities are particularly concerned about the threat from hundreds of French Islamic radicals who have traveled to Syria and returned home with skills to stage violence.
Though it was unclear who was responsible for Friday night's violence, the Islamic State is "clearly the name at the top of everyone's list," said Brian Michael Jenkins, a terrorism expert and senior adviser to the president of the Washington-based RAND Corporation.