PARIS – France’s President François Hollande decried the massacres across Paris as an “act of war” by the Islamic State, amplifying signals Saturdayy of a major response from France and its allies after coordinated gunfire and bombings that killed at least 127 people.
Moments later, a message attributed to the Islamic State asserted responsibility for the worst attacks in France since World War II and among of the worst terrorist strikes on Western soil since Sept. 11, 2001.
The Islamic State — in statements in Arabic and French — suggested the attacks had been in the planning stages, but gave no clear indication of whether Friday held any particular significance. It described Paris has the capital of a country that “carries the cross in Europe.”
A day after declaring a nationwide emergency, Hollande said the attacks had been “organized and planned from outside” and vowed “merciless” retaliation.
Hollande’s statement also marked the clearest sign that authorities could significantly boost the U.S.-led military effort to strike the Islamic State in Syria and Iraq.
The attacks, Hollande said, were “committed by a terrorist army, the Islamic State group, a jihadist army, against France, against the values that we defend everywhere in the world, against what we are: A free country that means something to the whole planet.”
France, meanwhile, is under its most serious lock-down in decades. Borders were sealed, many public sites were shut and soldiers took up positions Saturday after a wave of explosions, gunfire and hostage-taking in Paris.
At half a dozen sites across Paris — a soccer stadium, restaurants, a concert hall — the attackers carried out suicide bombings, hurled grenades and shot hostages dead in a frenzy of violence that paralyzed the city.
Late into the night and early Saturday morning, heavily armed security forces flooded the streets while panicked residents and tourists sought safety indoors.
Friday was the second time this year that the City of Light has been a scene of mass murder; in January, Islamist gunmen attacked the satirical newspaper Charlie Hebdo and a kosher supermarket, leaving a total of 17 dead.
The latest violence will only heighten the tension on a continent that is already on edge from the accumulated strain of a historic migration crisis, growing Islamist extremism and increasingly polarized politics.
“We are going to lead a war which will be pitiless,” Hollande said outside the Bataclan concert hall, scene of the most bloodshed.
“Because when terrorists are capable of committing such atrocities, they must be certain that they are facing a determined France, a united France, a France that is together and does not let itself be moved, even if today we express infinite sorrow.”
The violence was quickly celebrated online by backers of the Islamic State and other extremist groups. The scale and sophistication of the attacks will be likely to prompt questions about how the planning for such an operation evaded the scrutiny of French intelligence services.
Until the early hours of Saturday morning, some of the gunmen were thought to remain at large. But the Paris prosecutor’s office announced Saturday that all eight of the attackers had been killed — seven of them by detonating explosives.
Still, authorities warned that accomplices could remain at large. “To plan six attacks you need a lot of people involved, not only those who were at the spot,” said a senior European counter-terrorism official, who spoke on the condition of anonymity.
The killers traced an arc across the city, targeting lightly secured facilities where tourists and residents had been enjoying the sort of experiences and events that define Friday night in Paris on a cool November evening. Soccer games, concerts and evening meals were all violently disrupted by the sounds of explosions and gunfire.
The scene of the worst carnage was the 19th-century Bataclan concert hall, one of the city’s most famous music venues, where hundreds of people had gathered for a show by an American band, Eagles of Death Metal.
As attacks reverberated elsewhere in the city, gunmen stormed the building. Witnesses said three or four men, clad in black, used assault rifles to mow down audience members, shooting some as they dove to the floor seeking safety.
“There are survivors inside,” a man named Benjamin Cazenoves posted on his Facebook account, saying he was in the hall before police closed in. “They are cutting down everyone. One by one.”
Police surrounded the building and, amid the boom of explosions and rattle of gunfire, moved in. As they did so, the attackers blew themselves up with explosive belts, police said. Inside, officers found evidence of a massacre. Authorities initially said that 118 people were killed in the siege at the concert hall, but later revised that total down to 87.
Government personnel guided survivors of the attack, wrapped in gold-colored heat blankets, down the street to waiting buses. Several had blood spattered on their clothing. Some cried. Most declined to talk to reporters.
Hollande went on national television Friday night to announce a state of emergency, including restrictions at French borders and the deployment of the army. The president’s office said 1,500 French troops would hit the streets of Paris to back up police.
The border controls came amid growing signs across Europe that the continent’s tradition of free movement is at grave risk. Despite rules for passport-free travel, Sweden instituted border checks this week to better control an unprecedented flow of migrants from the Middle East, southern Asia and Africa. Slovenia rolled out razor wire on its border with Croatia.
While the new French border controls were expected to be strict, international airlines and trains appeared to still be operating.