Iraqi officials believe that an Islamic State (ISIS) car bomb, not a coalition airstrike, caused a March 17 blast in Mosul, according to a new report.

A coalition airstrike on that day had targeted a building with ISIS fighters holed up inside, after Iraqi forces coming under strong fire called for coalition air support. Initial reports blamed the strike for collapsing a building that killed civilians in a nearby building.

But an Iraqi military spokesman told DoD News, a Pentagon-run news service, that an examination of the site of the blast showed that an airstrike did not collapse the building; rather it fell due to a nearby ISIS bomb-laden vehicle at the time of the strike.

“There was no hole in the building,” Saeed al-Jayashi, a spokesman for the Iraqi military, told reporters traveling in Iraq with Marine Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff. “The strike was 100-percent accurate and it was correct.”

He also said the size of the weapon dropped could not have caused the kind of damage Iraqi troops found at the site.

However, Iraqi officials said the airstrike did set off the car bomb, which took out the whole block and killed 61 civilians. They also said people in the neighborhood told Iraqi forces that ISIS forced people into the collapsed building and made them stay.

The Iraqi officials’ assertions echo those made by U.S. military officials in recent days, that the coalition airstrike may not have caused the collapse of the building and the civilians deaths by itself.

The airstrike had triggered immense pressure and public scrutiny on the U.S. military, particularly over whether the Trump administration has loosened rules of engagement on how U.S. troops fight against ISIS.

Commanders say the rules have not changed since December under the Obama administration. Those rule changes allowed commanders at lower levels to approve airstrikes against ISIS targets versus having to go up the chain of command to higher-up commanders, which takes more time.

Officials say those rule changes have nothing to do with the civilian casualties that occurred on March 17.

“A rigorous process remains in place, even at the delegated level,” said spokesman Army Col. Joe Scrocca during a recent telephone briefing with reporters.

“These ROE changes did not remove any protections for civilians or allow the targeting of civilian buildings,” he said Thursday.

Scrocca also said ISIS is smuggling civilians into buildings and trying to bait the coalition into attacking the buildings to take advantage of the public outcry and deter action in the future.

He said the coalition caught the ISIS tactic on video and is working to declassify it.

The U.S.-led coalition is currently undergoing a formal investigation into the March 17 airstrike to review whether correct procedures were followed.

Jayashi said Iraqi investigators are still working to uncover the complete truth and will submit their full report to the prime minister soon.