Iranian state media initially reported that "
takfiri gunmen" executed the assault. Two groups claimed responsibility for the terrorist attack, including
Arab separatist militant group the
Arab Struggle Movement for the Liberation of Ahwaz (ASMLA) and the
Islamic State of Iraq and the Levant (ISIL). ASMLA then decided to deny responsibility for the attack.
Timeline of responsibility claims 22 September The claim of responsibility was first made through
Iran International TV by Yaqoub al-Tostari, the spokesperson for the ASMLA who spoke to the television on air, on the same day. He said the attack was conducted "because of the establishment's tyranny against Ahvazis". ANR is identified as a name used by the ASMLA. Habib Jaber al-Ka'abi, an ASMLA leader based in Denmark, tweeted in support for the attack and said it was against a "legitimate target". Following the claim by ISIL, Yaqoub al-Tostari who spoke with
Al Arabiya television as the ASMLA spokesperson said the ISIL involvement is false, adding that "The commando operation was carried out by the Ahzavi resistance movement. Civilians were killed as a result of indiscriminate gunfire from Iranian security forces", as quoted by
BBC Monitoring on 22 September 2018 at 16:17 (
GMT).
23 September A statement on the ASMLA website on 23 September denied responsibility for the attack, saying that the claim was made by a "group that was expelled from the organization since 2015". The denial happened after Iranian foreign ministry summoned the ambassadors of Denmark and the Netherlands in Tehran and protested them for hosting ASMLA.
26 September On 26 September, ISIL's
Al Furqan Media Foundation, which publishes official announcements from ISIL leaders, published an audio statement titled "The Muwahhidin's Assault on the Tower of the Mushrikin" from spokesman
Abul-Hasan Al-Muhajir, which claimed "A group of men of the
Khilafah and guardians of the creed in the land of Persia have pounced in defense of the religion, acting to deter and suppress their enemy and to fulfill the Islamic State's promise to all who have the blood of
Ahlus Sunnah on their hands."
27 September On 27 September, ISIL's newspaper
al-Naba released what it claimed were photos of the five masked attackers. ==Reactions==