Hooded gunmen attacked the Parisian office of the satirical magazine Charlie Hebdo on Wednesday, killing at least twelve, including two police officers and several of the paper’s staff, in what was described as the worst militant attack on French soil in decades.

President François Hollande denounced the attack as one of “indescribable barbarity” and terrorism and pledged the perpetrators would be “hunted for as long as it takes to catch them and bring them to justice.”

A video showed the gunmen leaving the scene after crying “Allah!” In another, they were heard shouting, “We have killed Charlie Hebdo. We have avenged the Prophet Muhammad.”

The men fled in a black Citroen that was later found abandoned by Paris police.

Blasphemous

The magazine is known for lampooning Islam and provoking religious extremists. Its offices were firebombed in 2011 after it put a caricature of the Prophet Muhammad on its cover.

Most Muslims consider making an image of Muhammad to be blasphemous.

The following year, France closed embassies and schools after Charlie Hebdo printed several more cartoons ridiculing Islam.

High alert

France was already on high terror alert after Islamic militants had urged attacks on the country in reprisal for its involvement in military operations against Islamists in Africa and the Middle East.

French forces are participating in strikes against Islamic State militants in Iraq and carrying out counterinsurgency operations across French-speaking West Africa.

President Hollande said several terrorist attacks had been foiled in the weeks before the attack on Charlie Hebdo. “We are threatened because we are a country of freedom,” he said.

Previous attacks

The last major attack in Paris was in 1995 when Algerian Islamists bombed a commuter train and killed eight passengers.

Two years ago, the lone wolf terrorist Mohamed Merah, a Muslim of Algerian descent, killed two French soldiers, a rabbi and three children in a shooting spree in Toulouse.