By Greg Botelho, CNN
Updated 11:16 AM ET, Wed January 7, 2015

Source: CNN
An eyewitness uploaded a video to Facebook that shows gunmen shoot a police officer and drive away.

(CNN)Hooded, black-clad gunmen burst into the office of a provocative French satirical magazine Wednesday, killing four cartoonists and eight others before heading off onto the streets of Paris.

While it wasn’t immediately clear who was behind the late morning attack, French officials viewed it as a blatant act of terrorism. And there were fears things could get worse, with the assailants still on the loose.

“We need to find the actors of this terrorist act,” French President Francois Hollande said. “They must be arrested and brought before judges and condemned as quickly as possible. France is shocked today.”

Latest update at 11:14 a.m. ET

  • The New York Police Department is adding extra officers at sensitive sites around the U.S. city, including the French Consulate, in response to the Paris attack, a law enforcement official told CNN. There is no known threat to New York at this time, the official added.
  • Charlie Hebdo editor and cartoonist Stephane Charbonnier, known as “Charb,” is among the dead in the attack, a police spokesman in the district where the office is located told CNN. At least three other well-known cartoonists — known by the pen names Cabu, Wolinski and Tignous — were also killed.
  • Police impounded a black Citroen in northeastern Paris similar to the one purportedly used by the attackers as a getaway car. Video from CNN affiliate BFMTV shows the vehicle being towed from Porte de Pantin, in Paris’ 19th district.
  • Interior Minister Bernard Cazeneuve said that all means are being used to “ensure as quickly as possible we can identify the (three attackers) and (arrest them), so that they can be punished with the severity that their barbarous acts are worthy of.”
  • In addition to the 12 dead, eight people were wounded, including four in critical condition, Cazeneuve said.