The so-called Islamic State group claimed responsibility on Thursday for two suicide bombings targeting a memorial service for an Iranian general killed in a 2020 US drone strike, the worst militant attack to strike Iran in decades as the wider Middle East remains on edge.

Experts who follow the group confirmed that the statement, circulated online among jihadists, came from the extremists, who probably hope to take advantage of the chaos gripping the region amid Israel’s war on Hamas in the Gaza Strip.

Wednesday’s attack in Kerman killed at least 84 people and wounded another 284.

It targeted a ceremony honouring Revolutionary Guard general Qassem Soleimani, seen as a hero by supporters of the country’s theocracy and viewed by the US military as a deadly enemy who aided militants who killed American troops in Iraq.

The IS group claims identified the two attackers as Omar al-Mowahed and Seif-Allah al-Mujahed.

The claim said the men carried out the attacks with explosive vests. It also used disparaging language when discussing Shiites, which the IS group views as heretics.

The statement did not say which regional arm of the extremists carried out the attack, which other claims in the past have.

The IS group, which once held vast territory across Iraq and Syria, ultimately were beaten back by US-led forces. It has been in disarray in the years since, though it has mounted major assaults.

Iran did not immediately acknowledge the claim.

An earlier report by the state-run IRNA news agency, later aired by state television, quoted an unnamed “informed source” saying that surveillance footage from the route to the service at Kerman’s martyrs cemetery clearly showed a male suicide bomber detonating explosives.

The official said the second blast “probably” came from another suicide bomber, though it had not been determined beyond doubt.

The gathering marked the fourth anniversary of the killing of Soleimani, the head of the Revolutionary Guard’s elite Quds Force, in a US drone strike in Iraq. The explosions happened as long lines of people gathered to mark the event.

Iranian state television and officials described the attacks as bombings, without immediately giving clear details of what happened.