ABC News January 7, 2015

Paris Attack Sparks #JeSuisCharlie Hashtag

WATCH: Suspects On the Run in Paris Terror Attack

The attack on satirical French magazine Charlie Hebdo has sparked outrage and mourning on social media, with supporters of the decades-old magazine tweeting under the hashtag #JeSuisCharlie, which translates to “I am Charlie.”

The magazine has long been the subject of threats and even attacks for poking fun at political and religious icons, including the prophet Mohammed.

@USEmbassyFrance/Twitter
The US Embassy in France posted a "Je Suis Charlie" image on their Twitter page, Jan. 7, 2015.
Gunmen Kill 12 at French Satirical Magazine 12 Dead in 'Terrorist' Attack on Paris Satirical Newspaper

After gunmen killed 12 people today at the magazine offices in a reported terrorist attack, supporters started to tweet out their backing for the magazine and for freedom of speech under the new hashtag.

Read More About the Charlie Hebdo Attack Here

Those that tweeted included reporters and media figures, but also readers passionate about the publication.

The magazine has a weekly print circulation of about 30,000. Its name refers to Charlie Brown from "Peanuts" and the French word for weekly newspaper, hebdomadaire.

A dark day for freedom of expression, an appalling human tragedy. #JeSuisCharlie #CharlieHebdo pic.twitter.com/IaTCXg8iD4

— amnestypress (@amnestypress) January 7, 2015

You can kill journalists, cartoonists. You can't kill the freedom of the press. You have only made their message stronger. #JeSuisCharlie

— Emily Koch (@EmilyKoch22) January 7, 2015

Une rose sur la place de la République #JeSuisCharlie pic.twitter.com/URQTQucLM4

— T Quinault Maupoil (@TristanQM) January 7, 2015