Senators have demanded the US military urgently reveals the findings of its probe into a deadly missile strike on an Iranian school.

At least 156 children and teachers were killed in the incident in Minab on 28 February, the first day of the war, according to Iranian officials.

The girls' school was next to a compound used by Iran's Revolutionary Guard Corps.

An initial US military investigation is understood to have found that its own Tomahawk missile was likely responsible.

According to Reuters sources, out-of-date intelligence was used by those creating "targeting packages".

More than two dozen Democratic senators have signed a letter demanding the investigation's findings are released within the next week, that Congress is briefed, and recommendations are made to stop a repetition.

"There is no justification for withholding an unclassified accounting ​of what happened, what went wrong, and what the Department is doing to prevent recurrence," the letter said.

They want Central Command chief Admiral Brad Cooper and defence secretary Pete Hegseth to provide an unclassified version of the findings to Congress and the public.

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'Utter horror and carnage' at school hit by missiles

"When a US strike kills civilians, the Department owes Congress, the American people, and the victims' families a clear accounting ‌of what happened and a credible plan ​to prevent future failures," the letter states.

If America's military is culpable, the senators said it would be the largest loss of civilian life since more than 400 people were killed when an air raid shelter was mistakenly bombed in Iraq in 1991.

A Pentagon official said the investigation was "ongoing" and no updates were currently available.

Admiral Cooper testified in May that the investigation was "complex" as the school was on an active Iranian missile base.

Donald Trump claimed in March, without evidence, that Iran had Tomahawk missiles and has suggested it may never be clear who was responsible.

"I don't think it was us," the president said last month, adding: "Somebody said it was our missile, ​maybe it wasn't our missile but I have seen nothing to lead me ​to believe it was."

Sky News has been to Minab to look at the evidence and speak to victims. Watch our documentary at 9pm on Thursday.

(c) Sky News 2026: Senators demand Pentagon reveals outcome of Minab school strike probe