[20] A report by The Washington Institute for Near East Policy said ISIS had uploaded a video of the perpetrator, identified by the alias "Abu Aisha Al-Umari", declaring allegiance to the Islamic State.

[22] However, Mohammad Gharawi, director of the New Generation Media Center said that ISIS "is now taking revenge for the fact that Iran contributed to its elimination in Iraq and Syria".

[13] On the other hand, the Institute for the Study of War assessed that the attack does not match the typical ISIS pattern and views it as an attempt to stoke sectarian tensions in Iran.

[28] According to state-affiliated media "large numbers of students and professors" reportedly took part in demonstrations denouncing the Shiraz terrorist attack.

[28] The United Nations Secretary-General António Guterres strongly condemned the terrorist assault on the Shah Cheragh Holy Shrine in Shiraz, Iran, which is claimed by the Islamic State.

The message said that targeting religious places is heinous and the Secretary-General emphasized: "bring[ing] to justice the perpetrators of this crime against civilians exercising their right to practice their religion".

"[32] Finland said that it was "Deeply saddened by the terrorist attack at the Shah Cheragh shrine in Shiraz" and it "strongly condemns terrorism in all its forms and manifestations".

[33] India strongly condemned the attack and extended condolences to Iran and urged the world "unite and combat terrorism in all its forms and manifestations".