American officers imagine that Wednesday’s bombing assault in Kerman, Iran, was almost certainly the work of the Islamic State — a preliminary evaluation based mostly on intelligence, in line with 4 American officers, who cautioned that no remaining conclusions have been drawn.

Two regional army officers additionally mentioned they believed the Islamic State had perpetrated the assault, which killed 84 individuals throughout a memorial ceremony on the tomb of Maj. Gen. Qassim Suleimani, who was assassinated 4 years in the past in an American drone assault.

Some Iranian leaders initially appeared accountable Israel for the assault, however the American officers mentioned early intelligence assessments indicated that Israel was not behind the explosions. Though Israel is believed to have often carried out covert operations in Iran, they’ve sometimes been focused operations towards particular people, Iranian scientists or officers, or strikes to destroy nuclear or weapons services.

The American officers, who spoke on the situation of anonymity to debate intelligence issues, cautioned that their evaluation on the bombings may evolve.

Iran held a nationwide day of mourning on Thursday to honor victims of the dual explosions, which occurred not solely at a tense second within the Center East, but in addition on a extremely symbolic day for some Iranians — the fourth anniversary of Common Suleimani’s demise. Common Suleimani, the highly effective army chief considered a malign drive within the West, is revered amongst many Iranians, particularly those that help the federal government.

Iranian officers had put the demise toll for the two blasts at 103 on Wednesday. However the inside minister, Ahmad Vahidi, mentioned on Thursday that 84 had been killed, in line with Tasnim, a semiofficial information company.

Talking throughout a go to to a hospital that was treating individuals wounded within the explosions, Mr. Vahidi mentioned the demise toll would possibly rise once more due to the grave situation of a number of the injured. A complete of 284 had been wounded within the assault, together with 220 nonetheless hospitalized in Kerman, a lot of whom had been in secure situation or requiring minor surgical procedures, he mentioned, in line with Tasnim.

Iran’s leaders continued denouncing what they known as a terrorist assault and promising to punish the perpetrators. However that they had not, to date, escalated their rhetoric towards Israel.

“The blind and spiteful act was to induce insecurity within the nation and take revenge on the love and devotion of the nice nation of Iran, particularly the zealous younger technology, to the martyr Qassim Suleimani,” learn a Thursday assertion from the Islamic Revolutionary Guards Corps, in line with Fars, one other semiofficial information company. The Revolutionary Guard Corps is the highly effective military-security equipment the place Common Suleimani was a prime chief.

Six Israeli officers, who spoke on the situation of anonymity to debate such intelligence issues, strongly denied that Israel had any position within the assault.

If the Islamic State was behind the bombing in Iran, it might symbolize a bloody resurgence for the group, which has been decimated by years of assaults from an American-led coalition within the area.

American officers mentioned that if the Islamic State did end up to have been accountable, it was unlikely that the group’s intention was to border Israel for the bombings or set off a wider warfare. As an alternative, it may have been seizing a chance to hit an enemy: The Islamic State, a Sunni Islamist group, has lengthy been against Iran, which has a Shiite Islamic authorities.

The group has claimed accountability for a number of earlier assaults on Iran, together with most not too long ago in October 2022, when a gunman killed 13 individuals at a shrine within the metropolis of Shiraz.

Mick Mulroy, who served as a Pentagon official within the Trump administration, mentioned the Islamic State may have carried out the assault, as a result of it has “no love misplaced” for Iran. “However it does appear to be an odd time to launch an assault with the present battle in Gaza and the unified Muslim help for the Palestinians,” he mentioned.

Colin P. Clarke, a counterterrorism analyst on the Soufan Group, a safety consulting agency based mostly in New York, mentioned he suspected the Islamic State’s Khorasan affiliate, also referred to as ISIS-Okay, as a possible perpetrator of the assault.

“ISIS-Okay has demonstrated each intent and functionality to assault targets inside Iran correct,” Mr. Clarke mentioned. “ISIS-Okay needs to assault Iran, as a result of Tehran is essentially the most distinguished Shia energy and the ire of ISIS-Okay’s extremely sectarian agenda. Extra so than different ISIS branches, ISIS-Okay propaganda repeatedly focuses on denigrating Shia as apostates.”

Mr. Clarke mentioned the assault on the commemoration ceremony, a extremely symbolic and sectarian goal given Common Suleimani’s stature because the architect of the Tehran-led Shiite axis within the area, match the group’s methodology of assaults.

However even when Israel — one in all Iran’s longtime archenemies — is just not accountable, Iran “is more likely to get a whole lot of propaganda mileage out of both immediately blaming the Israelis” or letting Iranians imagine that Israel was accountable, Mr. Clarke mentioned.

Tasnim, the information company, reported that the primary explosion occurred at 3:04 p.m. Wednesday as individuals crowded the street main towards Common Suleimani’s tomb. The second blast got here 13 minutes later, it mentioned.

One other semiofficial information company, IRNA, quoted a police spokesperson as saying that three cops had been killed within the explosions whereas attempting to assist different victims.

The commemoration ceremony was held to mark the fourth anniversary of Common Suleimani’s assassination in an American drone strike at Baghdad airport in January 2020. Comparable ceremonies honoring the overall are held yearly.

Leily Nikounazar, Eric Schmitt and David E. Sanger contributed reporting.