At least 12 dead as gunmen attack French satirical weekly that printed Mohammed cartoons

At least 12 people were killed when gunmen armed with Kalashnikovs and a rocket-launcher opened fire in the offices of French satirical weekly Charlie Hebdo on Wednesday.

French President Francois Hollande has labelled the shooting a terrorist attack, and confirmed that at least 11 people were killed and another four were in critical condition. Among the dead are two police officers.

"This is a terrorist attack, there is no doubt about it," Hollande told reporters.

The attackers may have known that today was print day at Charlie Hebdo, so the full editorial staff was reportedly on hand. French news organizations report that four of France's most well known cartoonists -- Stéphane Charbonnier, known as Charb, Jean Cabu, Georges Wolinski, and Bernard Verlhac, known as Tignous-- are among the dead.

Bernard Maris, the magazine’s deputy editor, was also killed. Five other staff at Charlie Hebdo are believed to be among the dead, but have not been named.

Hollande arrived at the scene of the shooting after rushing there and calling an emergency cabinet meeting, the presidency said.

The government raised its alert level to the highest possible in the greater Paris region.

A source close to the investigation said two men "armed with a Kalashnikov and a rocket-launcher" stormed the building in central Paris and "fire was exchanged with security forces."

Clad all in black with hoods, the attackers forced Corrine Rey to open the door to Charlie Hebdo's office building.

“I had gone to pick up my daughter at day care, arriving in front of the magazine building, where two masked and armed men brutally threatened us,” Rey, who draws under the name "Coco," said.

“They shot Wolinski and Cabu,” she added. “It lasted five minutes. I had taken refuge under a desk.”

Rey said the men spoke fluent French and claimed they were Al Qaeda terrorists.

A worker on the first floor of the building said he didn't hear any gunshots, but witnessed the gruesome aftermath.

"We did hear a bizarre noise, but no firing. Then when we went out we saw blood on the stairs. A lot of blood," he told The Guardian.

Video shows two gunmen shooting a Paris policeman from a distance, who is then seen struggling on a sidewalk. The two gunmen rush over to him, and one casually puts a bullet in the policeman's head, killing him.

"It was ghastly, awful. We knew it was serious because they weren’t even trying to take him away to hospital. They were just trying to save him right there in the street," a neighbor who saw paramedics trying to save the injured police officer told The Guardian.

In the video, the gunmen can be heard shouting "Allahu akbar" between bursts of gunfire. The gunmen also shouted "we have avenged the prophet," according to police.

A source said a gunman had hijacked a car and knocked over a pedestrian while attempting to speed away.

The New York Times reports that the car was later found abandoned "in the 20th Arrondissement of Paris, a neighborhood with a large immigrant population."

The publication's cartoonist Renaud Luzier earlier told AFP there were "casualties" after the incident.

The satirical newspaper gained notoriety in February 2006 when it reprinted cartoons of the Prophet Mohammed that had originally appeared in Danish daily Jyllands-Posten, causing fury across the Muslim world.

Its offices were fire-bombed in November 2011 when it published a cartoon of Mohammed and under the title "Charia Hebdo".

Despite being taken to court under anti-racism laws, the weekly continued to publish controversial cartoons of the Muslim prophet.

In September 2012 Charlie Hebdo published cartoons of a naked Mohammed as violent protests were taking place in several countries over a low-budget film, titled "Innocence of Muslims", which was made in the United States and insulted the prophet.

French schools, consulates and cultural centres in 20 Muslim countries were briefly closed along with embassies for fear of retaliatory attacks at the time.

Editor Stephane Charbonnier has received death threats and lives under police protection.

The newspaper's editor in chief, Gérard Biard, is in London. He was quoted on Twitter saying that the threats had actually lessened lately.

France's interior minister said police are searching for three suspects involved in the attacks.

Watch footage of the attack, via the Associated Press, below:

Watch footage, via NBC News, below:

With reporting by Agence France-Presse