UPDATED: NBC News has issued an updated statement saying the “information that was the basis of the account” that police killed one suspect and arrested two others in the wake of the Paris Charlie Hebdo attack could not be confirmed.

“Earlier Wednesday, two senior U.S. counterterrorism officials told NBC News that one of the suspects in the attack had been killed and that two others were in custody. However, the officials later said the information that was the basis of that account could not be confirmed,” wrote NBC News’ Pete Williams.

Officials have confirmed that the youngest of the three identified suspects, 18-year old Hamyd Mourad, turned himself in to authorities late Wednesday night in his hometown of Charleville-Mézières.

The other two suspects, Said Kouachi, 34, and Cherif Kouachi, 32, remain at large and France has issued photos of them and asked for the public’s help in finding them. Cherif Kouachi is well-known to French police for his involvement in terrorist groups.

An anti-terror raid was conducted late Wednesday night north of Paris in the town of Reims and searches were being carried out in the 19th district in Paris and in Charleville-Mezieres.

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 were Jean Cabut, aka Cabu, and Stéphane 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 the Islamic prophet Muhammad. Then in 2011, the magazine was fire-bombed after publishing a special issue titled Charia Hebdo with a caricature of Muhammad on the cover. Two years later, Charlie Hebdo published a comic book biography of Islam’s founder.