Islamic State terror group leaders responded this week to the hacking collective Anonymous’s threat to expose them by vowing a counterattack against the so-called hacktivists. An Islamic State-affiliated account on a messaging app, Telegram, transmitted a message indicating it would respond to Anonymous’ cyberwar threat, Newser reported Friday.

The message, written in Arabic, stated that ISIS operating in Syria and Iraq intended to declare themselves owners of the virtual world, according to a researcher interviewed by Business Insider. "I don't know if it is literally declaring virtual war on Anonymous, but it is promising a response," the researcher said. The terror group has also advised its followers on how to avoid falling for Anonymous’ hacking tricks.

Anonymous threatened the ISIS with cyberwar following last week’s coordinated terror attacks in Paris that left 130 people dead and wounded more than 350 others. ISIS claimed responsibility for the slaughter. The loose collective of online hackers has been tracking ISIS supporters for some time, and began shutting down Twitter accounts used by the group to spread its message around the world.

Telegram, the messaging app which has more than 50 million users, blocked 78 accounts it alleged were connected to the terror group, according to a Reuters report. Some of the accounts had more than 16,000 followers.

Calling their campaign Operation Paris, or #OpParis on social media, Anonymous said it wanted members of the collective to hack into Islamic State websites, steal valuable information and leak it online. Anonymous also released a how-to hacking guide Wednesday to help those wanting to join their cyberwar against the terrorist group.

The guide offers tips for novice hackers, including some HTML and Python programming language shortcuts. The guide also suggests that hackers use a Linux operating system when attempting to attack Islamic State group websites.