As IS have already claimed responsibility then it's going to take some 'impressive' propaganda to change the narrative. Maybe the bloodied terrorists will confess to working under instruction from Ukraine.
My limited understanding is that Russia is fighting Islamist groups all over Africa at the moment, having effectively pushed out the security forces of the old colonial powers. That combined with Syria and Chechnya must make Russia a fairly high priority target for IS and similar groups.
A couple of years ago Russia started to recruit Syrian Gov forces to fight against Ukraine At around the same
time Sheik Mansur started bringing in those "Syrian opposition forces" he'd fought alongside in that war.
Is it plausible that ISIS fighters have been fighting in one of the foreign legions against Russians ? Yes
And before someone jumps in with one of those idiotic "So what you are saying is" comments No this doesn't
mean Zelensky or the top brass have sanctioned or knew about this attack.
They are there for their own reasons and it's nothing to do with Freedom, Democracy, Sovereignty or protecting Europe.
Ukraine have been that desperate for fighters they'd even take me or even Classy Carra if he's interested