Parisians expressed shock, disgust and defiance in equal measure. Hundreds of soccer fans departing the stadium Friday night waved French flags and sang impromptu choruses of the national anthem, “Le Marseillaise.”

The next morning, hundreds queued outside a hospital near the Bataclan theater, scene of the most appalling violence, to donate blood. As a shrine of flowers expanded along the sidewalk, a lone guitarist sang John Lennon’s peace ballad, “Imagine.”

Hollande said the attacks meant France would increase its military efforts to crush IS. He said France — which besides bombing suspected IS targets in Syria and Iraq as part of the U.S.-led coalition also has troops fighting militants in Africa — “will be merciless toward the barbarians of Islamic State group.”

In an official statement the group said its fighters strapped with suicide bombing belts and carrying machine guns carried out the attacks in various locations in the heart of the capital which were carefully studied.

The attacks were designed to show France would remain a top target for the jihadist group as long as the country continued its current policies, the group said in a statement.

"To teach France, and all nations following its path, that they will remain at the top of Islamic State’s list of targets, and that the smell of death won’t leave their noses as long as they partake in their crusader campaign," said the group.

It said “eight brothers wearing explosive belts and carrying assault  rifles” conducted a “blessed attack on... Crusader France.” 

"As long as you keep bombing you will not live in peace," said one of the militants, identified as Abu Maryam the Frenchman.

"Terrorize them and do not allow them to sleep due to fear and horror," he added.

Speaking to the nation, Hollande said attacks on a stadium, concert hall and Paris cafe diners 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 is part of a US-led coalition conducting an air war against IS in  Syria and Iraq, where IS declared a caliphate last year after seizing swathes  of both countries.

It has carried out air strikes in Iraq for more than a year but extended  them to Syria in September. 

He said he would address parliament on Monday in an extraordinary meeting and the country would observe three days of official mourning.

As Hollande addressed the nation, French anti-terror police worked to identify potential accomplices to the attackers, who remained a mystery to the public.

Two French police officials say a Syrian passport was found on the body of one of the suicide bombers who targeted France’s national soccer stadium.

The identities and nationalities of the attackers have not been released. The police officials spoke on condition of anonymity because they weren’t authorized to be publicly named.

READ MORE: Tears, anger and solidarity: Hong Kong’s French community reacts to Paris terror attacks

A succession of near-simultaneous explosions and shootings across six locations across the city.

Islamic State released an undated video on Saturday threatening to attack France if bombings of its fighters continue, a day after gunmen and bombers killed at least 120 people in Paris.

French police are hunting possible accomplices of the eight assailants who terrorized Paris concert-goers, cafe diners and soccer fans in the deadliest peacetime violence to strike France.

A succession of near-simultaneous explosions and shootings across six locations across the city killed at least 120 and injured around 200 people.

World leaders united in sympathy and indignation, New York police increased security measures, and people worldwide reached out to friends and loved ones in France.

The violence raised questions about security for the millions of tourists who come to Paris and for world events routinely hosted in the normally luminous capital, where troops were deployed to support police trying to restore order.

One of Europe’s most heavily visited tourist attraction, the Disneyland theme park east of the capital, announced it would not open for business Saturday, a rarity.

Prosecutor’s office spokeswoman Agnes Thibault-Lecuivre said authorities couldn’t rule out the possibility that other militants involved in the attack remained at large. Detectives tried to identify lower-level accomplices who may have played support roles.

Supporters of the Islamic State militant group, which controls swathes of Iraq and Syria, said in Twitter messages that the group carried them out.

"The State of the caliphate hit the house of the cross," one tweet said.

French President Francois 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.

Reflecting fears in other European capitals of the risk of coordinated or copycat attacks, the British government scheduled its own emergency COBRA intelligence committee overseen by Prime Minister David Cameron.

Three suicide bombs targeted spots around the national stadium Stade de France, north of the capital, where Hollande was watching an exhibition soccer match between the French and German national teams.

Around the same time, fusillades of bullets shattered the clinking of wine glasses in a trendy Paris neighborhood as gunmen targeted a string of popular cafes, crowded on an unusually balmy November night. At least 37 people were killed, according to Paris Prosecutor Francois Molins.

The attackers next stormed a concert hall, the Bataclan, hosting the American rock band Eagles of Death Metal, opened fire on the panicked audience and took members 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.

At least one person lies writhing on the ground as scores more stream past, some of them bloodied or limping. The camera pans down the street to reveal more fleeing people dragging two bodies along the ground. Two other people can be seen hanging by her hands from upper-floor balcony railings in an apparent desperate bid to stay out of the line of fire.

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,”’ Sylvain 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.

After being whisked from the soccer stadium near the blasts, Hollande declared a nationwide state of emergency - the first in decades - and announced the closure of France’s borders to stop perpetrators escaping.

“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.

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 are 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.

President Barack 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 Disneyland Paris theme park announced it would not open for business Saturday but billed the move as a matter of sympathy, not of security. 

Disney said in a statement it would remain closed “in light of the recent tragic events in France and in support of our community and the victims of these horrendous attacks.” Some 14.2 million people visited the attraction last year.

READ MORE: President Xi Jinping condemns 'barbaric' terrorist attacks in Paris as world leaders offer condolences and support

Paris is expected to host 80 heads of state, including Obama, for a climate summit in two weeks. In June, France is to scheduled 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. 

French President Francois Hollande on Saturday told his Turkish counterpart by phone that he would send his finance and foreign ministers to the G20 summit in Turkey, Turkish presidential sources said.

President Tayyip Erdogan spoke to Hollande to offer his condolences.

"President Erdogan reiterated that terrorism had no religion or nation and that the Turkish people were standing behind France. Both leaders expressed their determination to tackle terrorism," one of the sources said.

READ MORE: Amid chaos, Parisians offer refuge to strangers via Twitter

Chinese President Xi Jinping offered his condolences to the victims and their families in a telephone call to Hollande, according to comments published on the Chinese foreign ministry website.

China is ready to join France and the international community in stepping up security cooperation and combating terrorism, Xi said.

There was no reports of Chinese casualties, China's state-run Xinhua news agency said, citing the Chinese embassy in the French capital. 

Ten tour groups from Hong Kong with a total of about 250 people were currently in Paris and all have reported they are safe, said Joseph Tung Yao-chung, Travel Industry Council executive director.

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.

“The big question on everyone’s mind is, were these attackers, if they turn out to be connected to one of the groups in Syria, were they homegrown terrorists or were they returning fighters from having served” with the Islamic State group, Jenkins said. “That will be a huge question.” 

Watch: Fans sing La Marseille, the French national anthem, as they evacuate Stade de France

"There were bodies everywhere," he said. “I saw 20 to 25 bodies lying on the floor and people were very badly injured, gunshot wounds.”

“Some of them were dead. Some of them were very badly wounded, but it was a bloodbath.”

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 dominos," he told Reuters. He said he saw people shot in the leg, shoulder, back and several people lying on the floor apparently dead.

There was no immediate verifiable claim of responsibility but supporters of the Islamic State militant group which controls swathes of Iraq and Syria said in Twitter messages that the group carried them out.

"The State of the caliphate hit the house of the cross," one tweet said.

Camille, 25, said: “My sister is in the Bataclan. I phoned her. She said they opened fire. And then she hung up.”

Two explosions were heard near the Stade de France in the northern suburb of Saint-Denis, where the France-Germany friendly 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 rumours of the attack spread, and spectators were held in the stadium and assembled spontaneously 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. Police appeared to be still searching for suspects later.

There were also unconfirmed reports of shooting in other locations, including the central Les Halles shopping centre.

The Paris carnage came within days of attacks claimed by Islamic State militants on a Shi’ite Muslim district of southern Beirut in Lebanon, and a Russian tourist aircraft which crashed in Egypt’s Sinai Peninsula.

Earlier on Friday, the United States and Britain said they had launched an attack in the Syrian town of Raqqa on a British Islamic State militant known as "Jihadi John" but it was not certain whether he had been killed.

Reuters, Associated press, Agence France-Presse