U.S. President Donald Trump said on Wednesday that it may never be determined who was responsible for the deadly strike on a girls’ school in Minab, southern Iran, on February 28, the first day of the Iran war, that killed more than 175 children and teachers.

The remarks, made to reporters, follow a Reuters report in March that an internal U.S. military investigation had found American forces were likely at fault, citing the use of outdated targeting data. The Pentagon has since elevated the probe but has not confirmed any preliminary findings, and no final determination has been made public.

“I don’t know that they are ever going to solve that problem in terms of whose fault it was because there were missiles flying all over the place,” Trump said. He added that he had “seen nothing to lead me to believe” U.S. forces were responsible, despite the initial investigation. “I don’t think it was us,” he said.

The strike, which occurred as American and Israeli forces attacked Iran, killed more than 175 children and teachers according to Iranian officials. A deliberate attack on a school would likely constitute a war crime under international humanitarian law. U.S. officials have publicly stated that Washington would never intentionally target a school.

The incident drew global condemnation, with the UN human rights office calling it “absolutely horrific.” Trump initially claimed without evidence that Iran was to blame, later stating he would accept the inquiry’s results while insisting no one purposefully attacked the school.