The fire appeared to have started by a blaze of fireworks that accompanied the bride and groom’s slow dance. The venue, like many buildings in Iraq, was constructed in part from flammable panels, the Iraqi News Agency reported. It later collapsed under the heat of the blaze.

“We saw the fire pulsating, coming out of the hall. Those who managed got out and those who didn’t got stuck. Even those who made their way out were broken,” Imad Yohana, a 34-year-old who fled the blaze, told Reuters.

Authorities declared a three-day mourning period as looping scenes of the blazing wedding hall played on television screens across the nation.

Prime Minister Mohammed Shia al-Sudani said Wednesday that he had ordered an investigation into its causes. His predecessor, Mustafa al-Kadhimi, had done the same after fires ripped through two hospital wards, killing scores, but with few obvious results.

Iraq’s political parties routinely siphon vast sums from the country’s budget through corrupt contracts that either deliver cut-rate services or do not deliver at all. In the construction sector, this means that cheap — and often flammable — materials are often favored. Civil defense officials say that fire safety measures in most government buildings are minimal to absent.

On Wednesday, Health Ministry spokesman Said al-Badr said that most seriously injured wedding guests had been transferred to major health centers.

Videos from the scene showed firefighters combing the wreckage as armed officials stood guard on a street lined with emergency vehicles. Charred metal dangled from the ceiling of the burned-out building.