The youngest of the three men suspected of carrying out the deadly attack on the offices of Charlie Hebdo has handed himself in.

Brothers Said Kouachi and Cherif Kouachi, both in their 30s, and Hamyd Mourad, 18, are believed to be behind the attack.

Mourad is reported to have surrendered following anti-terror raids in Reims, but two men remain at large.

Reports in France have claimed one of the brothers had previously been tried on terrorism charges.

Cherif Kouachi was charged with criminal association related to a terrorist enterprise in 2005 after he was arrested before leaving for Iraq to join Islamist militants.

He was sentenced to 18 months in prison in 2008, according to French media.

During his trial, he told the court he "really believed in the idea" of fighting the US-led coalition in Iraq.

He said he was outraged at the torture of Iraqi inmates at the US prison at Abu Ghraib near Baghdad.

They are believed to be linked to a Yemeni terrorist network, backed up by the testimony of one witness who told reporters he heard the gunmen shouting: "You can tell the media that it's al Qaeda in Yemen".

Survivors of the attack said the men shouted "Allahu akbar" as they fired.

The attackers used fluent, unaccented French as they called out the names of specific employees before shooting them.