(JTA) — At least 12 people died in an attack on the Paris headquarters of the Charlie Hebdo satirical magazine.

Footage from the scene of the attack shows two armed men exiting a black car and shooting a rifle at a police officer near the building. One of the assailants then approached the officer and shot him in the head, in the video of the attack Wednesday posted on the French news website Jssnews.com.

Ten people also were wounded in the attack, five in serious condition.

The assailants escaped the scene. The identities of the victims have not yet been made known.

Two of the 12 people reported killed were police officers, according to the French daily Le Monde. Employees of the satirical magazine also are reported killed.

According to the Le Monde report, the assailants cried out “Allah is the greatest” and that their attack was to “avenge the prophet.”

In September 2012, the newspaper, which regularly runs articles and caricatures critical of religion, published a series of satirical cartoons of the Muslim prophet Mohammed.

French President François Hollande, speaking live near the scene of the shooting, said it was a terrorist attack, adding that “France is today in shock.”

Charlie Hebdo, he added, “was threatened several times in the past and we need to show we are a united country.” He also vowed that French authorities “will punish the attackers. We will look for the people responsible.”

According to Le Monde, the attack on the Charlie Hebdo offices is the bloodiest to have taken place in France since 1835.