Terrorist organisation ISIS has issued a death threat to Twitter co-founder Jack Dorsey as well as company employees for frequently deleting their accounts from the micro-blogging service.

Twitter’s terms of service disallow users from posting “direct, specific threats of violence against others,” and the company deletes posts that feature videos of the terrorist group’s acts of violence and suspends their accounts as quickly as possible.

The post was uploaded on JustPaste, and features an image of Dorsey with the cross-hairs of a gun superimposed on it. It reads, “

Your virtual war on us will cause a real war on you.

“You started this failed war. We told you from the beginning it’s not your war, but you didn’t get it and kept closing our accounts on Twitter, but we always come back.

“When our lions [brave men] come and take your breath, you will never come back to life.”

Twitter has taken threat seriously and a spokesman revealed that their security team is investigating the veracity of these threats with relevant law enforcement officials.