Paris, January 7 (RHC-Xinhua) -- French President Francois Hollande said on Wednesday that the shooting at the headquarters of a French newspaper is "a terrorist attack."

Twelve people have been confirmed dead in the attack on the headquarters of Charlie Hebdo on Wednesday morning. Another four are reportedly in a critical condition.

Denouncing the "shocking attack," Hollande said France raised the anti-terrorism alert in the greater Paris area to the highest level after the shooting amid fears of more attacks.

Vigipirate, France's national security alert system, has been raised to Scarlet, its highest level which means a definite threat, in the greater Paris area, announced Matignon earlier.

France, the target of Islamist fighters in reprisal for its military strikes against Islamist strongholds in Iraq and the Sahel region, has aborted several terror attacks in recent weeks, Hollande said.

Charlie Hebdo was firebombed in 2011, due to publishing a controversial series of cartoons depicting the Prophet Mohammed.