U.S. President Donald Trump expressed scepticism on Wednesday that responsibility would ever be assigned for the February 28 airstrike on a girls’ school in Minab, Iran, which killed more than 175 children and teachers on the opening day of the U.S.-Israeli assault on the country. His remarks cast further uncertainty over a U.S. military investigation that, according to an initial probe, likely holds American forces responsible.

Trump told reporters that it might never be known “whose fault was it because there were missiles flying all over the place.” He said he had seen “nothing to lead me to believe it was” a U.S. missile that struck the school, even as Reuters reported in March that the Pentagon’s preliminary inquiry pointed to the possible use of outdated targeting data. The Pentagon has since escalated the investigation but has not publicly confirmed any findings.

The school bombing drew immediate global condemnation. Iranian officials counted more than 175 dead, including children and educators. The United Nations human rights office called the strike “absolutely horrific” and noted that deliberately targeting a school would amount to a war crime under international humanitarian law. U.S. officials have repeatedly stated they would not intentionally hit such a site.

Trump initially blamed Iran for the incident without evidence, later claiming that “nobody” purposefully attacked the school and that he would accept the investigation’s outcome.