Hostage-taking in French town, Hebdo suspects sighted

A helicopter with members of the French intervention gendarme forces hover above the scene of a hostage taking at an industrial zone in Dammartin-en-Goele, northeast of Paris January 9, 2015. [Photo/Agencies]

US television network ABC reported that the brothers had been listed in the databases for "years."

Dave Joly, a spokesman for the Terrorist Screening Center, said he could neither confirm nor deny if the Kouachis were listed in counter-terrorism databases.

While world leaders described Wednesday's attack on the weekly newspaper Cahrlie Hebdo as an assault on democracy, al Qaeda's North Africa branch praised the gunmen as "knight(s) of truth".

Charlie Hebdo, where journalists were gunned down during an editorial meeting, had been firebombed in the past for printing cartoons that poked fun at militant Islam and some that mocked the Prophet Muhammad.

Two of those killed were police posted to protect the paper.

On Thursday, US President Barack Obama made an unannounced visit to the French Embassy in Washington to pay his respects.

He wrote in a condolence book: "As allies across the centuries, we stand united with our French brothers to ensure that justice is done and our way of life is defended. We go forward together knowing that terror is no match for freedom and ideals we stand for - ideals that light the world."

Amid local media reports of isolated incidents of violence directed at Muslims in France, President Francois Hollande and his Socialist government have called on the French not to blame the Islam faith for the Charlie Hebdo killings.

Hollande has held talks with opposition leaders and, in a rare move, was due to invite Marine Le Pen, leader of the resurgent anti-immigrant National Front, to his Elysee Palace for discussions on Friday.