The Islamic State has found time between killing hostages and trying to acquire chemical weapons to vow a counterattack against Anonymous. An ISIS-affiliated account on messaging app Telegram sent out a memo telling members to change their Twitter photos to an image of a black shoe print on the French flag, adding that the terrorist group plans to respond to Anonymous’ cyber war. In an Arabic message, it “states that there will be something coming and that we should stay tuned and watch out as [ISIS] declares themselves as the owners of the virtual world,” a researcher on ISIS tells Business Insider. “I don’t know if it is literally declaring virtual war on Anonymous, but it is promising a response.”

She adds ISIS is “definitely trying to taunt Anonymous,” which has been attacking social media accounts linked to the terrorist group. Telegram—which boasts more than 50 million users who can share messages that disappear after a certain amount of time, per Tech Insider—has apparently been doing the same. The company blocked 78 accounts “being used by ISIS to spread their propaganda” this week alone, including some with more than 16,000 followers, reports Reuters.