DUBAI, United Arab Emirates (AP) — Mourners in black began gathering Tuesday for days of funerals and processions for Iran’s late president, foreign minister and others killed in a helicopter crash, a government-led series of ceremonies aimed at both honoring the dead and projecting strength in an unsettled Middle East.

For Iran’s Shiite theocracy, mass demonstrations have been crucial since millions thronged the streets of Tehran to welcome Grand Ayatollah Ruhollah Khomeini in 1979 during the Islamic Revolution, and also attended his funeral 10 years later. An estimated 1 million turned out in 2020 for processions for the late Revolutionary Guard Gen. Qassem Soleimani, who was slain in a U.S. drone strike in Baghdad.

Whether President Ebrahim Raisi, Foreign Minister Hossein Amirabdollahian and others draw the same crowd remains in question, particularly as Raisi died in a helicopter crash, won his office in the lowest-turnout presidential election in the country’s history and presided over sweeping crackdowns on all dissent. Prosecutors already have warned people over showing any public signs of celebrating his death and a heavy security force presence has been seen on the streets of Tehran since the crash.

But Raisi, 63, had been discussed as a possible successor for Iran’s supreme leader, the 85-year-old Ayatollah Ali Khamenei. His death now throws that selection into question, particularly as there is no heir-apparent cleric for the presidency ahead of planned June 28 elections.

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“Raisi’s death comes at a moment when the Islamist regime is consolidated,” wrote Alex Vatanka, an Iran expert at the Middle East Institute. “In short, there will be no power vacuum in Tehran; nonetheless, post-Khamenei Iran suddenly looks far less predictable than it did just a few days ago.”

A procession Tuesday morning led by a semitruck carrying the caskets of the dead slowly moved through the narrow streets of downtown Tabriz, the closest major city near the site of the crash Sunday. Thousands in black slowly walked beside the coffins, some throwing flowers up to them as an emcee wept through a loudspeaker for men he described as martyrs. On Wednesday, a funeral presided over by Khamenei will turn into a procession as well.

The caskets later arrived in Tehran to an honor guard at the airport and then went onward to the holy Shiite seminary city of Qom. There, a semitruck surrounded by soldiers in fatigues at one point was swarmed by a crowd of mourners. Some beat their chests and wailed. The truck later picked up speed while others stood alongside the road, watching.

The bodies will return to Tehran on Tuesday night for services Wednesday.

It remains unclear what international presence that funeral will draw, as Raisi faced U.S. sanctions for his part in mass executions in 1988 and for abuses targeting protesters and dissidents while leading the country’s judiciary. Iran under Raisi also shipped bomb-carrying drones to Russia to be used in its war on Ukraine.

“I don’t feel comfortable sending condolences while Iran is sending drones that are used against civilians in Ukraine,” wrote Lithuanian Foreign Minister Gabrielius Landsbergis on the social platform X.

United Kingdom Security Minister Tom Tugendhat echoed that in his own message on X: “President Raisi’s regime has murdered thousands at home, and targeted people here in Britain and across Europe. I will not mourn him.”

On Thursday, Raisi’s hometown of Birjand will see a procession, followed by a funeral and burial at the Imam Reza shrine in the holy city of Mashhad, the only imam of the Shiite’s faith buried in Iran.

That shrine has long been a center for pilgrims and sees millions visit each year. Over the centuries, its grounds have served as the final burial site for heroes in Persian history. It’s an incredibly high, rare honor in the faith. Iranian President Mohammad-Ali Rajai, the only other president to die in office when he was killed in a 1981 bombing, was buried in Tehran.

Iran’s theocracy declared five days of mourning, encouraging people to attend the public mourning sessions. Typically, government employees and schoolchildren attend such events en masse, while others take part out of patriotism, curiosity or to witness historic events.

Across Iran, its rural population often more closely embraces the Shiite faith and the government. However, Tehran has long held a far different view of Raisi and his government’s policies as mass protests have roiled the capital for years.

The most recent involved the 2022 death of Mahsa Amini, a woman detained over her allegedly loose headscarf, or hijab. The monthslong security crackdown that followed the demonstrations killed more than 500 people and saw over 22,000 detained. In March, a United Nations investigative panel found that Iran was responsible for the “physical violence” that led to Amini’s death. Meanwhile, Iran’s rial currency has cratered after the collapse of Iran’s nuclear deal with world powers, destroying people’s savings and pensions.

On Sunday night, as news of the helicopter crash circulated, some offered anti-government chants in the night. Fireworks could be seen in some parts of the capital, though Sunday also marked a remembrance for Imam Reza, which can see them set off as well. Critical messages and dark jokes over the crash also circulated online.

Iran’s top prosecutor has already issued an order demanding cases be filed against those “publishing false content, lies and insults” against Raisi and others killed in the crash, according to the semiofficial ISNA news agency.

No cause has yet been offered by Iran’s government for the crash, which took place in a foggy mountain range in a decades-old helicopter. Iranian presidents including hard-liner Mahmoud Ahmadinejad and Abolhasan Banisadr both survived their own helicopter crashes while in office.

Iran’s military, not its civil aviation authority, will investigate and later offer a report, authorities say. Iran’s civil air crash investigators faced widespread international criticism over their reports on the downing of a Ukrainian passenger plane by an air defense battery in 2020 after Soleimani’s killing.

Meanwhile Tuesday, Iran’s new Assembly of Experts opened its first session after an election that decided the new assembly, a panel of which both Raisi and the late Tabriz Friday leader Mohammad Ali Ale-Heshem were members. A flower-ringed portrait sat on the seat Raisi would have occupied at the meeting of the 88-member panel, which is tasked with selecting the country’s next supreme leader. Acting President Mohammad Mokhber also attended.