U.S. President Donald Trump said on Wednesday it may never be determined who was responsible for the February 28 airstrike on a girls’ school in southern Iran that killed more than 175 children and teachers, despite an internal Pentagon investigation that initially found American forces were likely to blame.

Trump disputed the preliminary U.S. military assessment reported by Reuters in March. “I don’t think it was us,” he told reporters at the White House. “There were missiles flying all over the place, and it’s horrible what happened, but I have seen nothing to lead me to believe it was.” He added: “I don’t know that they are ever going to solve that problem.”

The strike on the Minab school came on the first day of the U.S.-Israeli offensive against Iran. Iranian officials said the death toll exceeded 175, mostly girls and their teachers. Reuters revealed that a preliminary U.S. investigation indicated outdated targeting data likely led American forces to hit the school. The Pentagon has not publicly confirmed those findings and says a formal probe is ongoing.

International condemnation was swift. The U.N. human rights office called the attack “absolutely horrific.” Trump initially claimed without evidence that Iran itself was responsible, but later said he would await the inquiry’s results and insisted nobody intentionally targeted the school. Deliberately striking a school would likely be a war crime under international humanitarian law.