As disturbing as the slaughter of innocents in Russia is, there are ominous signs that this attack is part of a new wave of ISIS-K attacks. ISIS-K formally emerged in the Afghanistan-Pakistan area in 2015, bringing together a group of disgruntled jihadists who opposed the Taliban and pledged loyalty to the then-ascendant Islamic State’s self-declared caliphate in Iraq and Syria. They embrace a far more radical version of jihadism than even the Taliban, opposing any accommodation with states or entities they see as Islam’s enemies and embracing sectarianism, among other beliefs. These legitimate concerns, however, must be seen in the context of significant progress against the broader jihadist movement, including the Islamic State itself.

--SSP alum Daniel Byman in Lawfare