Microblogging site Twitter said Sunday night that the company was working with law enforcement agencies to investigate an alleged death threat from the Islamic State group to its co-founder Jack Dorsey and other employees, CNBC reported Monday. The militant group reportedly called on its sympathizers around the world to target Twitter employees for blocking ISIS-related accounts.

The alleged threat, which was first reported by Buzzfeed, was posted on pastebin, a Poland-based website that is popular among programmers for storing and sharing snippets of source codes. “Your virtual war on us will cause a real war on you,” the post reportedly read. The message was reportedly accompanied by a digitally altered image of Dorsey inside a red target circle. However, it was unclear who posted the threat message.

"Our security team is investigating the veracity of these threats with relevant law enforcement officials,” Twitter said, in a statement to CNBC. Dorsey has not reportedly addressed the alleged threat against him.

Twitter had reportedly suspended dozens of pro-ISIS accounts in the last few months after execution videos of hostages and propaganda material was circulated online. The company's terms of service ban all users who promote direct, specific threats of violence against others.”

The post reportedly condemned Twitter for taking down ISIS-linked accounts and warned, “We normally appear back.”

“For the ‘individual jihadi’ all over the world, target the Twitter company and its interests in any place, people, and buildings, and don’t allow any one of the atheists to survive,” the post said, according to Buzzfeed.