France has raised its alert to the highest level after a deadly shooting incident in central Paris that killed 12 people and is being called a terrorist attack.

Police and a witness say masked gunmen with automatic weapons stormed the offices of a French satirical newspaper that has previously drawn condemnation from Muslims.

Xavier Castaing, head of communications for the Paris police prefecture, confirmed the deaths in the shooting at the offices of Charlie Hebdo, which had been repeatedly threatened for publishing caricatures of the Prophet Muhammad, among other controversial sketches.

French President Francois Hollande who headed to the scene, says 'several terrorist attacks were thwarted in recent weeks.' Top government officials planned an emergency meeting and France has reinforced security at houses of worship, stores, media offices and transportation.

An official of the SBP police union, says the attackers escaped in two vehicles.