It’s said that no terrorist organization utilizes the internet to recruit members and spread its propaganda as effectively as ISIS, especially when it comes to social media platforms Facebook and Twitter. But the sites’ continued fight against Islamic State has led to a group of ISIS-affiliated hackers releasing a video threatening retaliation for this defiance.

In the 25-minute clip, made by the ‘Sons of Caliphate,’ images appear featuring CEOs Mark Zuckerberg and Jack Dorsey riddled with bullet holes. The group has also promised to “take ten” accounts for every one of theirs that Facebook and Twitter remove, until the sites have been “deleted.”

"To Mark and Jack, founders of Twitter and Facebook and to their Crusader government. You announce daily that you suspend many of our accounts. And to you we say: Is that all you can do. You are not in our league," the overwritten text states.

"If you close one account we will take 10 in return and soon your names will be erased after we delete you sites, Allah willing, and will know that we say is true [sic]."

The video also claims that the group controls more than 10,000 Facebook accounts, 150 Facebook groups, and 5000 Twitter profiles.

Both Twitter and Facebook have launched campaigns to combat the promotion of terrorist activities. Microblogging site Twitter, which is a one of the most popular methods for Islamic State to spread its propaganda, has shut down 125,000 accounts since the middle of last year "for threatening or promoting terrorist acts, primarily related to ISIS."

Both social media giants have received threats similar to this one before; an ISIS statement from 2015 showed a picture of Jack Dorsey overlaid with the sights from a gun. But these reactions from the group show that the anti-terror campaigns are obviously having an effect, and will likely cause Facebook and Twitter to pour more resources into removing ISIS material.