UPDATED: 1:15 p.m. EST / 7:15 p.m. CET
AT A GLANCE:
The gunmen escaped after the attack, and French authorities have launched a sweeping manhunt.
In rallies across France, people have signs reading: "Je Suis Charlie" (I am Charlie) in support of magazine that was attacked.
Ten journalists were killed, including the editor in chief and at least four cartoonists.
Twelve people are dead following what France's president is calling a "terror attack" on satirical magazine Charlie Hebdo in Paris on Wednesday. A massive manhunt is underway for the gunmen, who are still at large.
The masked gunmen shouted "Allahu akbar!" as they stormed the building, killing 10 journalists and two police officers, security officials confirmed. The magazine staff was in an editorial meeting, around lunchtime in Paris, when at least two gunmen opened fire. Eleven others were wounded, four of those injuries are serious.
Witnesses said the gunmen spoke perfect French.
Charlie Hebdo has frequently drawn condemnation from Muslims. In 2011, the magazine was attacked after it ran a cartoon depicting Muḥammad. There was no immediate claim of responsibility, and was condemned by world leaders as an attack on freedom of expression, but praised by supporters of the militant Islamic State group.
French President Francois Hollande said "several terrorist attacks were thwarted in recent weeks" but this is of exceptional barbarity. In response, France has raised its alert to the highest level, reinforcing security at houses of worship, stores, media offices and public transportation.
Authorities say their No. 1 priority at this point is locating the gunmen, who abandoned their car in northern Paris.
Footage from the scene
Video taken from a nearby rooftop, shows two men firing from rifles in the street below. The gunmen get out of a black hatchback parked in middle of street, rifles in hand, shooting as they go at a building.
As they fire, a man cowers on the street. One of the gunmen shoots the man in the head. They yell out to others before both getting into the car and speeding off.
Stills from eyewitness video show two #CharlieHebdo attackers wearing hoods & black clothing shoot a wounded man pic.twitter.com/IX8Wys3p5M— Mashable News (@MashableNews) January 7, 2015
A search for the gunmen is underway throughout the entire city. The area around the offices, in the 11th arrondissement, has been sealed off.
People in nearby buildings and offices are tweeting photos from the scene the photo below shows an office window damaged by bullets.
Ils ont tiré à deux reprises les balles ont traversé la porte et la fenêtre pic.twitter.com/Jhgi4MBlnp— yve cresson (@yvecresson) January 7, 2015
"Outrageous attack on press freedom"
The weekly magazine, for years a fixture of the liberal left in France, mocked politicians, business tycoons, military leaders, political conservatives and religious figures. Its cartoon covers often shocked and offended, usually, it seemed, on purpose.
ISIS has threatened to attack France and minutes before the attack, Charlie Hebdo had tweeted a satirical cartoon of that extremist group's leader giving New Year's wishes.
Meilleurs vœux, au fait. pic.twitter.com/a2JOhqJZJM— Charlie Hebdo (@Charlie_Hebdo_) January 7, 2015
The cartoon entitled "Still No Attacks in France" had a caricature of an extremist fighter saying "Just wait — we have until the end of January to present our New Year's wishes."
Last drawing by Charb (killed at Charlie) "Still no attack in France. Wait! We can send best wishes till end of Jan" pic.twitter.com/1qCesfb22N— Julien Pain (@JulienPain) January 7, 2015
In a statement, NATO Secretary General called the attack "barbaric" and an "outrageous attack on press freedom."
The victims
Officials have started to identify the victims of the attack. Two officers and ten journalists, including the editor of the magazine and four cartoonists, were killed.
What we know so far about the victims of the #CharlieHebdo terror attack: http://t.co/tqdgWcwa4R pic.twitter.com/FQk5Peo8m5— Mashable News (@MashableNews) January 7, 2015
The gunmen reportedly took over the intercom system and called out names of journalists at the office.
Gunmen responsible for Charlie Hebdo massacre in Paris called out victims' surnames before executions. Included ed Stéphane Charbonnier, 47.— Peter Allen (@peterallenparis) January 7, 2015
#JeSuisCharlie
Hours after the attack, #JeSuisCharlie, which translates "I am Charlie," started trending online. Many of the messages called for unrestricted freedom of the press in light of the attack. Others shared some of the well-known satirical cartoons published by Charlie Hebdo as a sign of their support for the magazine.
Charlie Hebdo's website has been updated with just a splash image that reads: "Je Suis Charlie."
The U.S. embassy in France changed its Twitter avatar in a show of support as well.
World leaders respond
British Prime Minister David Cameron, who met with German Chancellor Angela Merkel in London on Wednesday, tweeted his condolences, saying the event was "sickening."
The murders in Paris are sickening. We stand with the French people in the fight against terror and defending the freedom of the press.— David Cameron (@David_Cameron) January 7, 2015
Angela Merkel and I met today. We're united in our condemnation of the horrifying Paris murders. pic.twitter.com/oSM2us6I8I— David Cameron (@David_Cameron) January 7, 2015
Queen Elizabeth also offered her condolences after the attack in a statement released by the palace:
Prince Philip and I send our sincere condolences to the families of those who have been killed and to those who have been injured in the attack in Paris this morning. We send our thoughts and prayers to all those who have been affected -- Elizabeth R
U.S. President Obama, who was briefed about the attack in the early morning, called the tragedy "horrific" and said the administration was at hand to assist French officials if needed.
"For us to see the kind of cowardly and evil attacks that took place today reinforces why its so important to stand in solidarity," Obama said. "The fact that this was an attack on journalists... these terrorists fear freedom of speech and freedom of the press."