Gunmen and bombers attacked restaurants, a concert hall and a sports stadium at locations across Paris on Friday, killing 127 people in a deadly rampage that President Francois Hollande was the work of Islamic State.
There was no immediate claim of responsibility, but Islamic State released an undated video in which a militant said France would not live peacefully as long it took part in U.S.-led bombing raids against its fighters.
A Paris city hall official said four gunmen systematically slaughtered at least 87 young people at a rock concert at the Bataclan concert hall. Anti-terrorist commandos launched an assault on the building. The gunmen detonated explosive belts and dozens of shocked survivors were rescued, while bodies were still being removed on Saturday morning.
Some 40 more people were killed in five other attacks in the Paris region, the official said, including an apparent double suicide bombing outside the Stade de France national stadium, where Hollande and the German foreign minister were watching a friendly soccer international. Some 200 people were injured.
The coordinated assault came as France, a founder member of the U.S.-led coalition waging air strikes against Islamic State in Syria and Iraq, was on high alert for terrorist attacks ahead of a global climate conference due to open later this month.
It was the worst such attack in Europe since the Madrid train bombings of 2004, in which 191 died.
Hollande said the death toll stood at 127. Officials said eight assailants had died, seven of whom had blown themselves up with explosive belts at various locations, while one had been shot dead by police. It was not clear if all the attackers were accounted for.
"The terrorists, the murderers raked several cafe terraces with machine-gun fire before entering (the concert hall). There were many victims in terrible, atrocious conditions in several places," police prefect Michel Cadot told reporters.
After being whisked from the stadium near the blasts, Hollande declared a national state of emergency - the first since World War Two. Border controls were temporarily reimposed to stop perpetrators escaping.
Local sports events were suspended, the rock band U2 canceled a concert, the Paris metro railway was closed and schools, universities and municipal buildings were ordered to stay shut on Saturday. However some rail and air services were expected to run.
"This is a horror," the visibly shaken president said in a midnight television address to the nation before chairing an emergency cabinet meeting.
He later went to the scene of the bloodiest attack, the Bataclan music hall, and vowed that the government would wage a "merciless" fight against terrorism.
Sylvestre, a young man who was at the Stade de France when bombs went off there, said he was saved by his cellphone, which he was holding to his ear when debris hit it.
"This is the cell phone that took the hit, it's what saved me," he said. "Otherwise my head would have been blown to bits," he said, showing the phone with its screen smashed.
French newspapers spoke of "carnage" and "horror". Le Figaro's headline said: "War in the heart of Paris" on a black background with a picture of people on stretchers.
Emergency services were mobilized, police leave was canceled, 1,500 army reinforcements were drafted into the Paris region and hospitals recalled staff to cope with the casualties.
Radio stations warned Parisians to stay at home and urged residents to give shelter to anyone caught out in the street. The hashtag #porteouverte (open door) started up on Twitter to offer people a place to stay.
The deadliest attack was on the Bataclan, a popular concert venue where the Californian rock group Eagles of Death Metal was performing. The hall is near the former offices of the satirical weekly Charlie Hebdo, target of a deadly attack by Islamist gunmen in January.
Some witnesses in the hall said they heard the gunmen shout Islamic chants and slogans condemning France's role in Syria.
France has been on high alert ever since the attacks on the Charlie Hebdo newspaper and a kosher supermarket in Paris in January killed 18 people.
Those attacks briefly united France in defense of freedom of speech, with a mass demonstration of more than a million people. But that unity has since broken down, with far-right populist Marine Le Pen gaining on both mainstream parties by blaming immigration and Islam for France's security problems.
It was not clear what political impact the latest attacks would have less than a month before regional elections in which Le Pen's National Front is set to make further advances.
The governing Socialist Party and the National Front suspended their election campaigns.
Hollande canceled plans to travel to Turkey at the weekend for a G20 summit.
U.S. President Barack Obama and German Chancellor Angela Merkel led a global chorus of solidarity with France. U.N. Secretary-General Ban Ki-moon condemned the "despicable attacks" while the Vatican called the killings "mad terrorist violence".
Italy tightened security measures.
Julien Pearce, a journalist from Europe 1 radio, was inside the concert hall when the shooting began. In an eyewitness report posted on the station's website, Pearce said several very young individuals, who were not wearing masks, entered the hall during the concert, armed with Kalashnikov assault rifles and started "blindly shooting at the crowd".
"There were bodies everywhere," he said.
The gunmen shot their victims in the back, finishing some off at point-blank range before reloading their guns and firing again, Pearce said, after escaping into the street by a stage door, carrying a wounded girl on his shoulder.
Toon, a 22-year-old messenger who lives near the Bataclan, was going into the concert hall with two friends at around 10.30 p.m. (2130 GMT) when he saw three young men dressed in black and armed with machine guns. He stayed outside.
One of the gunmen began firing into the crowd. "People were falling like dominoes," he told Reuters. He saw people shot in the leg, shoulder and back, with several lying on the floor, apparently dead.
There was no immediate verifiable claim of responsibility but supporters of Islamic State said in Twitter messages that the group carried them out.
"The State of the caliphate hit the house of the cross," one tweet said.
Two explosions were heard near the Stade de France in the northern suburb of Saint-Denis, where the France-Germany soccer match was being played. A witness said one of the detonations blew people into the air outside a McDonald's restaurant opposite the stadium.
The match continued until the end, but panic broke out in the crowd as rumors of the attack spread, and spectators who were held in the stadium assembled on the pitch.
Police helicopters circled the stadium as Hollande was rushed back to the interior ministry to deal with the situation.
In central Paris, shooting erupted in mid-evening outside a Cambodian restaurant in the capital's 10th district.
Eighteen people were killed when a gunman opened fire on Friday night diners sitting at outdoor terraces in the popular Charonne area nearby in the 11th district.
The prosecutor mentioned five locations in close proximity where shootings took place around the same time.
The Paris carnage came within days of attacks claimed by Islamic State militants on a Shi'ite Muslim district of southern Beirut, and a Russian tourist aircraft which crashed in Egypt.
Earlier on Friday, Kurdish fighters retook the Iraqi town of Sinjar from Islamic State and the United States and Britain launched an air strike on a British Islamic State militant known as "Jihadi John", but it was not certain if he had been killed.