PARIS - At least 11 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.
President Francois Hollande, who immediately headed to the scene of the shooting in Paris, described it as a "terrorist attack." Hollande said 11 people were killed and another four were in critical condition after the attack, branding it an "act of exceptional barbarism" and calling an emergency cabinet meeting.
He called for "national unity" as the government raised its alert level to the highest possible in the greater Paris region. He added that "several terrorist attacks had been foiled in recent weeks".
Wednesday's shooting is one of the worst attacks in France in decades.
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".
The source said a gunman had hijacked a car and knocked over a pedestrian while attempting to speed away. He added that two police officers had died in the attack.
Television footage showed large numbers of police in the area, bullet-riddled windows and people being carried away on stretchers.
The gunmen shouted "we have avenged the prophet," according to a police source. It was not immediately clear what happened to the attackers.
In the first reaction from abroad, British Prime Minister David Cameron condemned the shooting. "The murders in Paris are sickening.
We stand with the French people in the fight against terror and defending the freedom of the press," he said in a message on Twitter.
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.
This week's front page featured controversial author French Michel Houellebecq, whose latest book "Soumission", or "Submission," which imagines a France in the near future that is ruled by an Islamic government, came out Wednesday.
The book has widely been touted as tapping into growing unease among non-Muslim French about immigration and the rise of Islamic influence in society.