Gunmen and bombers attacked restaurants, a concert hall and a sports stadium at locations across Paris on Friday, killing at least 128 people in what a shaken President Francois Hollande called an unprecedented terrorist attack.

Another 99 were in critical condition, a source at the prosecutor's office said on Saturday.

A Paris city hall official said gunmen systematically slaughtered nearly 100 people attending a rock concert at the Bataclan music hall. Anti-terrorist commandos eventually launched an assault on the building, killed the gunmen and rescued dozens of shocked survivors.

Some 40 other people were killed in up to five other attacks in the Paris region, the city hall official said, including an apparent double suicide bombing outside the national stadium where Hollande and the German Foreign Minister were watching a friendly soccer international.

Paris Public Prosecutor Francois Molins said the overall death toll was at least 120. Five assailants had been "neutralized".

The apparently coordinated assault came as France, a founder member of the U.S.-led coalition waging air strikes against Islamic State fighters in Syria and Iraq, was on high alert for terrorist attacks ahead of a global climate conference due to open later this month.

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. 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.

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.

All 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.

It was unclear whether any gunmen were still on the loose.

Radio stations broadcast warnings to Parisians to stay home and leave the streets and urged residents to give shelter to anyone caught out in the street.

The deadliest attack was on the Bataclan, a popular concert venue where the Californian rock group Eagles of Death Metal was performing. The concert hall is just a few hundred meters from the former offices of the satirical weekly Charlie Hebdo, which was the target of a deadly attack by Islamist gunmen in January.

Witnesses in the hall heard the gunmen shout Islamic slogans and slogans condemning France's role in Syria.

"We know where these attacks come from," Hollande said, without naming any individual group. "There are indeed good reasons to be afraid."

HIGH ALERT

France has been on high alert ever since the attacks on Charlie Hebdo newspaper and a Kosher supermarket in Paris in January killed 18 people.

Hollande canceled plans to travel to Turkey at the weekend for a G20 summit. He called an emergency meeting of his national security council for 9 a.m. (0800 GMT) on Saturday.

US President Barack Obama and German Chancellor Angela Merkel led a global chorus of solidarity with France and U.N. Secretary-General Ban Ki-moon condemned the "despicable attacks" and demanded the release of the hostages.

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 while the concert was under way armed with Kalashnikov assault rifles and started "blindly shooting at the crowd".

"There were bodies everywhere," he said.

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.(4.30 p.m. ET) 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.

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 rumors 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 center.

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