Masked gunmen wielding Kalashnikovs and a rocket launcher killed at least 12 people and injured 10 more at the Paris offices of satirical French newspaper Charlie Hebdo on Wednesday before escaping. French president François Hollande called the shooting "unquestionably a terrorist attack."

Video published by BFMTV and Le Monde, said to be from outside the Charlie Hebdo offices, shows two masked gunmen with large rifles. A longer, more graphic version of the video shows what appears to be the killing of a police officer; you can find it here.

Another video from the scene shows at least two gunmen shooting in the open street and shouting what might be "Allahu Akbar":

Two of the dead are policemen; the French cartoonists Cabu, Tignous, Wolinski, and Charb (the magazine's publisher) are all reported dead. A policeman at the scene of the shooting told reporters "it's carnage."

Authorities are in pursuit of the gunmen, who wounded a police officer and hit a pedestrian in their escape. Security levels have been raised at houses of worship in Paris

Charlie Hebdo is well-known for its intentionally offensive cartoons of the prophet Muhammad; in 2011, its offices were fire-bombed after it published the following cover, on which a cartoon Muhammad says "100 lashes if you don't die laughing":

Update, 9:04 a.m.: This week's issue of Charlie Hebdo depicts a caricature of Michel Houellebecq, the author of Submission, a new novel imagining an Islamic France in 2022 and a Muslim president that has been criticized as being anti-Muslim.

Gerard Biard, the magazine's editor-in-chief, told the Press Association that the publication had not received any threats prior to today's attack.

"Not to my knowledge, and I don't think anyone had received them as individuals, because they would have talked about it," he said. "There was no particular tension at the moment."

Photos identifying the Charlie Hebdo staff killed by the gunman have also been released by Agence France-Presse:

Update, 9:24 a.m.: Designer Corinne Rey who works in the building where the Charlie Hebdo offices are located tells French newspaper L'Humanité that the shooters forced her at gunpoint to enter the code to open the building's door. "They spoke French perfectly ... claiming to be Al-Qaida."

Le Monde reports that the gunmen attacked during a staff meeting, and apparently knew them all by name.

Update, 9:39 a.m.: French interior minister Bernard Cazeneuve told reporters that three gunmen are responsible for "this barbaric act."

Update, 10:19 a.m.: Agence France-Presse reports economist and writer Bernard Maris was also killed in the attack.

Agnes Thibault-Lecuivr, a spokeswoman for the Paris prosecutor's office, also confirmed to the Guardian the 12-person death count in today's shooting carried out by three gunmen.

"We heard shouting in the street," Benoît Bringer, who works at a press agency on the same floor as the magazine's offices, told France Info radio. "We saw hooded men carrying Kalashnikovs entering the building. We called the police. After a few minutes we heard heavy firing – a lot of firing, a hell of a lot. We went upstairs to take shelter on the roof. Then after about 10 minutes we saw two armed men come out onto the street. There was more shouting, more firing.

Update, 11:11 a.m.: Some 3000 police officers are currently on a manhunt for the gunmen in the streets of Paris.

Update, 12:54 p.m.: At press conference Wednesday evening, Paris prosecutor François Molins confirmed the timeline of events to reporters. From the Guardian:

He said two gunmen entered the offices of Charlie Hebdo at 11.30am. They killed one person in the welcome area before climbing to the second floor, where the paper was holding an editorial meeting. It is believed the gunmen knew the time and place of the meeting.

The gunmen opened fire with Kalashnikovs, Molins said. He said they shouted "Allahu Akbar" and said "they were avenging the Prophet." Separate video captured one gunman saying the same outside the building after the shooting.

Twelve were killed, 11 wounded, and four are in serious condition, Moulin said. The dead included eight journalists. Autopsies were to be held Thursday morning.