Twitter founder Jack Dorsey has been threatened with death because the company blocks ISIS social media accounts, BuzzFeed first reported on Sunday.
The social media site has suspended users linked to terrorism in the past.
The Islamic State threat went live on pastebin 15 hours ago, and calls on jihadists across the world to rally in a fight against Twitter. Pastebin is an anonymous online site favoured by coders. The page basically declares war on Twitter.
BuzzFeed reports that the post has now been shared by ISIS supporters, but its exact author hasn't been identified yet. So far the page, which features an image of the Twitter logo and what appears to be Dorsey's face covered by a gun target symbol,has had around 1,750 views.
The post is written in Arabic, though Google translate (not entirely accurate) paints a basic picture of what it says. One extract reads: "Jack helpless when their necks officially become a target for the soldiers of the Caliphate and supporters scattered among your midst." The word Caliphate has both religious and political connotations and describes a strict Muslim government led by a Caliph, a successor to the prophet Muhammed.
Later in the post, the writer talks about a "media war" and says that by stopping ISIS and its supporters from tweeting their messages, employees are "preventing the delivery of the holy mission to the world." At the time of writing, Dorsey's Twitter feed suggests he's not acknowledged the attack.
Twitter told us that it is looking into the threats. "Our security team is investigating the veracity of these threats with relevant law enforcement officials," a spokesperson said in an email to BI UK.
It's not the first time Twitter employees have been threatened by ISIS. CEO Dick Costolo has said in the past that the militants have spoken out about being prevented from spreading their jihadist movement online. Costolo has talked about "balancing free speech and open speech with wider concerns."