About 19,000 French websites have been hit with cyberattacks since last week's attacks in Paris left 20 dead, including some of the nation's most notable cartoonists who worked for satirical magazine Charlie Hebdo, said France’s cyberdefense chief, who called it an unprecedented surge in hacks.

“That’s never been seen before,” Adm. Arnaud Coustilliere said, according to the Associated Press. “This is the first time that a country has been faced with such a large wave of cyber-contestation.”

The cyberattacks, some carried out by well-known Islamic hacker groups, mostly involved minor denial-of-service attacks, and affected a range of websites, from military regiments to pizza shops.

The announcement came as French President François Hollande promised that the country would protect all religions and vowed to "severely punish" any anti-Muslim or anti-Semitic acts. “French Muslims have the same rights as all other French,” Hollande said, according to the BBC. “We have the obligation to protect them.”

France remains on edge since the Jan. 7 attack at the offices of Charlie Hebdo, the satirical magazine that has angered some Islamic extremists for its caricatures of the Muslim Prophet Muhammad. Some Muslims believe their faith forbids depictions of the prophet. The magazine, which lost eight staff members, sold out of a 5 million print run of its first edition since the attacks.

The magazine was burying several slain staff members Thursday, including cartoonists Bernard Verlhac, Georges Wolinski, columnist Elsa Cayat and Franck Brinsolaro, a police officer assigned to protect Charlie Hebdo’s editor, Stéphane Charbonnier, who was among 12 people killed last week when gunmen stormed his magazine's offices in Paris. Four Jewish customers at a kosher store were also killed and several others taken hostage in a separate attack.

In the days following the Charlie Hebdo attack, there have been a string of terrorism and threats across France, which has about 5 million Muslims. In total, 17 people were killed by at least three terror suspects over three days, including the attack at the magazine, a Jewish supermarket and a policewoman who was on patrol. The three gunmen were also killed. Muslim organizations in France have rushed to condemn the attack on the magazine, which had been firebombed in 2011 after publishing cartoons lampooning Islam.