A poster allegedly originating from the Islamic State (IS) group has surfaced on social media, threatening Russia with attacks.

This comes shortly after the Islamist group claimed responsibility for the assault on a concert center in Moscow. The poster, reportedly disseminated by Iranian media citing Al Azaim, an IS-Khorasan propaganda network, has been widely shared by various users, including Ukrainian internal affairs advisor Anton Gerashchenko. Moreover, it has garnered significant attention on Russian Telegram channels.

IS-Khorasan, established in Afghanistan in late 2014, has asserted responsibility for the recent attack on the Crocus Center in Moscow, resulting in the deaths of at least 137 individuals.

According to reports from the state-run TASS news agency, four suspects from Tajikistan are facing terrorism charges and have all admitted guilt. However, there are allegations that they appeared in court bearing signs of physical abuse and coercion.

The poster, purportedly representing the sentiments of the militants, vows to carry out further terrorist acts against Russia in response to the alleged torture and mistreatment of IS members during interrogation.

A Russian language version of the message widely shared is headlined “Threat to all cruel Russians, including Putin” in front of an image of a masked man holding a knife. Underneath, the poster says, “Be warned; do not think that we do not have the opportunity to avenge our brothers held hostage. With Friday’s attack, we showed you that with the permission of Allah, the mujahadeen of the Islamic State can punish you for your savagery.”

The Russian Telegram channel Supernova Plus shared the image, stating that the Islamist group intends to “orchestrate another terrorist attack in the Russian Federation” as a response to the alleged torture and interrogation of its members.

This announcement comes after IS released a graphic video depicting attackers firing on the crowd inside the concert hall, a video deemed authentic by media outlets such as the BBC.

Despite this, no Russian official has supported the IS claim. Kremlin spokesman Dmitry Peskov stated on Monday that it would be inappropriate to comment on the matter until the investigation is concluded.