Police have killed one suspect and arrested two others in the mass shooting that claimed the lives of 12 people at Charlie Hebdo, the French satirical magazine, senior U.S. officials told NBC Nightly News.
An anti-terror raid was conducted late Wednesday night north of Paris in the town of Reims.
The three suspects were previously identified as French nationals Said Kouachi, 34, and Cherif Kouachi, 32, and Hamyd Mourad, 18. All three men are reportedly from Aubervilliers, a French suburb.
A police source told Le Monde that searches are being carried out in the 19th district in Paris and in Charleville-Mezieres, the hometown of the youngest suspect.
French President Francois Hollande delivered a speech on French TV late Wednesday, calling the attacks an act of "exceptional barbarism."
France will hold a national day of mourning on Thursday.
A flurry of peaceful demonstrations were being held Wednesday evening to pay homage to the victims as the international creative community condemned the killing spree.
President Obama said that he reached out to Hollande to offer "every bit of assistance" to "America's oldest ally."
"The fact that this was an attack on journalists, an attack on our free press also underscores the degree to which these terrorists fear freedom, of speech and freedom of the press," Obama said.
The attackers stormed the headquarters of Charlie Hebdo with assault rifles while the editorial team was having its weekly meeting. Among those killed, Jean Cabut, aka Cabu, and Stephane Charbonnier, aka Charb, two of France's best-known and most talented comic strip artists and caricaturists.
A fierce advocate for free speech, Charlie Hebdo was founded in 1969 and is known for its satirical, and often controversial, cartoons.
In 2006, it sparked a large controversy following the publication of 12 caricatures of Prophet Muhammad. Then in 2011, the magazine was fire-bombed after publishing a special issue titled Charia Hebdo with a caricature of Prophet Muhammad on the cover. Two years later, Charlie Hebdo published a comic book biography of Islam's founder.