The Daesh terrorist group claimed responsibility for two blasts that killed over 100 people attending a commemoration ceremony for slain Iranian commander Qassem Soleimani in Iran's Kerman on Wednesday.
The group posted a statement on its affiliate Telegram channels.
The blasts ripped through crowds who had come to honor Soleimani, four years after a targeted U.S. drone strike in Baghdad killed the veteran senior commander of the Islamic Revolutionary Guard Corps.
Investigators have confirmed that the first blast, which struck at around 2:45 p.m. (1115 GMT) some 700 meters (yards) from Soleimani's grave, was detonated by a "suicide bomber," the official IRNA news agency reported Thursday.
Investigations are continuing into the trigger for the second explosion but it was "very probably another suicide bomber," IRNA said, citing an "informed source."
Iran's supreme leader Ayatollah Ali Khamenei on Wednesday blamed "evil and criminal enemies" of Tehran, without naming them, and vowed a "harsh response."
In mid-2014, Daesh terrorists overran large swathes of northern Iraq and Syria.
In recent years, they suffered major territorial losses and military defeats to Western forces in Syria and neighboring Iraq.
However, its operatives occasionally unleash attacks in both countries.