Update: Deadly attack on office of French magazine Charlie Hebdo Called out by name and executed: Cartoonists who mocked Islam were slaughtered where they stood for 'insulting Prophet'

Gunned down after terrorists asked for them by name, the four cartoonists who mocked Islam and refused to be threatened by 'Koranic law' 

Four of France's most revered cartoonists - Stephane Charbonnier, Georges Wolinski, Bernard 'Tignous' Verlhac and Jean Cabut - were among 12 people executed by masked gunmen in Paris today at the offices of satirical magazine Charlie Hebdo.

Two masked men brandishing Kalashnikovs burst into the magazine's headquarters this morning, opening fire on staff.

Police officers were involved in a gunfight with the men, who escaped in a hijacked car, speeding away towards east Paris and remain on the loose, along with a third armed man.

Charbonnier, 47, known by his pen name Charb, was the editor of the weekly magazine, and once famously said 'I'd prefer to die standing than live on my knees'. He also stressed 'I live under French law, not Koranic law'.

Cabut, also called Cabu, its lead cartoonist and Wolinski an 80-year-old satirist who had been drawing cartoons since the 1960s.

There are reports that the gunmen asked for the cartoonists by name before shooting them dead.

The killers were heard to shout: 'The Prophet has been avenged.' 

And there were unconfirmed reports that one of the gunmen said to a witness: 'You say to the media, it was Al Qaeda in Yemen.' 

Radio France chief executive Mathieu Gilet announced on Twitter that a contributor, Bernard Maris, was another of the victims. 

President Francois Hollande described the bloodbath as a 'barbaric attack against France, and against journalists'.