(REUTERS) – Gunmen and bombers attacked restaurants, a concert hall and a sports stadium at locations across Paris on Friday, killing at least 120 people in what a shaken French President Francois Hollande called an unprecedented terrorist attack.

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.