Iranian President Ebrahim Raisi and Revolutionary Guard Corps (IRGC) Commander Hossein Salami vowed revenge during the funeral of the victims of the Kerman attack.
About 100 people were killed in Kerman on Wednesday at a memorial for al-Quds Force Commander Qassem Soleimani, who was killed in a US airstrike in Baghdad in early 2020.
On Thursday, ISIS claimed responsibility for the two explosions, saying two militants detonated explosive belts in the crowd that gathered at the cemetery in the southeastern Iranian city of Kerman on Wednesday.
- Arrests in five governorates
Interior Minister Ahmed Vahidi announced the arrest of some individuals in connection with the deadly twin bombing.
Speaking on state television, Vahidi reported that "good clues" helped identify the persons involved in the attack without mentioning their nationalities or places of arrest.
An hour later, the official IRNA news agency quoted Iran's Deputy Interior Minister for Security Affairs, Majid Mirahmadi, saying the country's intelligence forces had identified and arrested "different individuals" in five provinces who were linked to the "terrorist attack" and had backed up the operations.
- Accusing the US and Israel
Also at the ceremony, Commander Hossein Salami vowed Iran would "take revenge for the terrorist attack."
Salami addressed ISIS militants, asserting that: "We will find you wherever you are," and the terrorist organization acts as an "agent" of the US and Israel.
He indicated that the US was defeated in Iraq, Afghanistan, Lebanon, Syria, and Yemen at the hands of Soleimani, adding that Washington was unable to achieve its goals of imposing sanctions on Iran.
Meanwhile, Raisi said the initiative is in the hands of Iran's powerful forces, who will determine the time and place to take revenge on the enemy.
Raisi claimed that the US, after creating the "usurping Israeli regime in the region by misusing the name of the Jews, sought to implement the current of ISIS," but Soleimani did a great job and disrupted the enemy's plan."
He said the "end of the Al-Aqsa Flood will also be the end of the Zionist regime."
State television broadcast footage shows crowds of families in Kerman crying for their loved ones in front of coffins wrapped in the Iranian flag.
The mourners chanted: "Revenge... Revenge,Death to America," and "Death to Israel," according to Reuters.
The Iranian Emergency Organization said the death toll reached 89 people, including 12 children.
- Delicate timing
Iran usually accuses Israel and the US of supporting anti-Iranian armed groups, which have carried out attacks in the past.
In October 2022, ISIS claimed responsibility for a bloody attack at a shrine in Shiraz, southern Iran, which killed 15 people, weeks after the Mehsa Amini protests broke out across the country.
Last August, gunmen again attacked the shrine Shiraz, killing three civilians.
In 2017, ISIS also claimed responsibility for two bombings that targeted the parliament headquarters and the shrine of Khomeini, the founder of the Islamic Republic.
Iranian members of ISIS carried out the attacks.
- Doubts about ISIS's responsibility
The Tasnim Agency, affiliated with the IRGC, wrote that the Zionist entity, after carrying out the Kerman attack, ordered ISIS to claim responsibility to escape the consequences of the attack.
The agency referred to the ISIS statement, saying the terrorist organization would say Persia or Khorasan when referring to Iran. It noted that the organization never published blurred pictures of those who carried out suicide attacks.
ISIS has never been more than 30 minutes late in publishing adoption statements, according to Tasnim, noting that the organization publishes a photo of the operative and the adoption statement immediately after the attack.
ISIS's method of carrying out attacks is to threaten first, issue a fatwa, carry out the operation, and then publish a statement claiming responsibility.
- Conspiracy theory
Iran Supreme Leader representative and Friday prayer preacher in Tehran, Ahmed Khatami, vowed the perpetrators would face a painful fate.
Khatami added that ISIS is an agent of the US and Israel, noting that the terrorists received treatment in Israel when they were injured in Syria.
Meanwhile, former head of the National Security and Foreign Relations Committee, Heshmatollah Falahatpisheh, told the ILNA agency that Iran is facing a new terrorist war against the US and Israeli intelligence services, Mossad.
He indicated that when they face a problem, they carry out actions against Iran, especially since the US and Israelis received a blow from Soleimani.
- “ISIS - Khorasan Province”
More details about the authors of the attack and their motives could not be immediately established.
However, Aaron Zelin, an expert with the Washington Institute for Near East Policy think tank, said he would not be surprised if the attack was mounted by the Islamic State branch based in neighboring Afghanistan, known as ISIS-Khorasan, or ISIS-K.
Zelin told Reuters that Tehran accused ISIS-K of being behind many foiled plots in the last five years. Most of those arrested were Iranians, Central Asians, or Afghans from the Afghanistan-based affiliate's network rather than from the group's Iraq and Syria network.
A Taliban crackdown has weakened ISIS-K inside Afghanistan, forcing some members to move to neighbouring states, but the group has continued plotting operations outside the country, according to US officials.
In Washington, White House spokesman John Kirby told reporters the United States was in no position to doubt Islamic State's claim that it was responsible for Wednesday's attack.
The US stressed Wednesday that it was not involved in any way in the two bombings.
The State Department rejected any accusations against Washington or Tel Aviv being involved in the attack, considering it "ridiculous."
The Israeli government did not comment on the attack.