In a first, the Islamic State has formally claimed an attack in Oman, a country that has had little history of security threats posted by jihadist groups- something that is itself unsurprising given that jihadists, who are Sunnis, do not draw on the native Omani population that primarily follows a different sect of Islam (Ibadism). The attack itself was directed at members of the country’s Shi‘a community- derogatorily dubbed ‘Rafidites’ (and specifically intended to refer to Twelver Shi‘a).
Rather than being part of some sophisticated Gulf/Arabian Peninsula-specific strategy or necessarily indicative of a broader trend in the region, the attack is more simply a reflection of the group’s worldview that the Shi‘a- as a supposed ‘apostate’ sect- are to be attacked wherever and whenever possible with the ultimate goal being that no Shi‘a should be left on earth. So long as the attackers can successfully execute the attack and prove their allegiance to the Islamic State in doing so, that becomes sufficient grounds for the attack to be formally claimed by the organisation. In this case, there was clear value in claiming the attack given that it had no precedent in the country in question and that it emphasises the global and eternal nature of the group’s war against Shi‘a.
Below are the relevant Islamic State materials translated. Any parenthetical insertions in square brackets are my own.