This terrifying video captures the moment gunmen stormed the office of French magazine Charlie Hebdo before killing at least 11 people today.
Journalist Martin Boudot was on a rooftop overlooking the building when two men clad in black and jumped out of a car and opened fire.
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Clad all in black and wearing masks, the attackers shouted 'Allahou Akbar' before entering the office of the satirical publication in central Paris.
Another video showed a woman running from the gunfire to cower behind a car.
French media report "a number of fatalities," and the official death toll is 11 dead, with five people in a critical condition.
Witnesses say they heard sustained gunfire at the office as the attackers opened fire with Kalashnikov assault rifles.
The weekly magazine has previously courted controversy with its depiction of news and current affairs.
French TV channel iTELE quoted a witness as saying he saw the incident from a building nearby in the heart of the French capital.
"About a half an hour ago two black-hooded men entered the building with Kalashnikovs (guns)," Benoit Bringer told the station.
"A few minutes later we heard lots of shots," he said, adding that the men fled the building.
Prime Minister David Cameron joined the condemnation of the attack, saying: "The murders in Paris are sickening. We stand with the French people in the fight against terror and defending the freedom of the press."
Deputy Prime Minister Nick Clegg said the killings were a "barbaric attack on freedom of speech".
"My thoughts are with the victims, their families and their colleagues," he said.
The publication has launched a series of attacks on Muslim extremism and the last tweet on its profile page @Charlie-Hebdo-, sent about an hour before the shootings, included a satirical cartoon of Islamic State leader Abu Bakr al-Baghdadi.
In it he wishes everyone "good health".
A police official, Luc Poignant, said he was aware of one journalist dead and several injured, including three police officers.
"It's carnage," Poignant told BFM TV.
In December 2011, its office was firebombed after it said the Prophet Muhammad would be editor-in-chief of its next issue.
The French media reports that the assailants fled from the scene in a black car and are now on the run.
The area has been cordoned off by police.
President of the National Assembly Claude Bartolone said: "Scenes of horror at the offices of Charlie Hebdo. My solidarity is with the victims."
Charlie Hebdo is a satirical comedy weekly newspaper and features cartoons and irreverent stories and frequently lampoons religions of all types.
It first ran from 1969 to 1981, when it folded, but the publication was resurrected in 1992.
The editor is Stephane Charbonnier.
There have been a number of shootings in the France over the past few years. in March 2012 Mohammed Merah, 23, a French man of Algerian descent, shot and killed a rabbi, two of his children, and another child at a Jewish school, in Toulouse, France, Police believe he had earlier shot and killed three paratroopers.
Merah said he was a member of Al Qaeda and that he was seeking revenge for the killing of Palestinian children.
