The strike - which killed at least 168 people, mostly children - "evoked a visceral horror", Volker Türk said.
19 hours ago
Tom Bennett
Anadolu via Getty Images
The UN's human rights chief has urged the US to conclude its investigation and publish its findings into a deadly strike on an Iranian primary school that happened on the first day of the war last month.
The bombing "evoked a visceral horror", Volker Türk said at an urgent UN Human Rights Council debate, adding that there "must be justice for the terrible harm done".
The attack on Shajareh Tayyebeh school consisted of two missile strikes in quick succession that killed at least 168 people, including about 110 children, Iranian officials have said.
US media have reported that American military investigators believe its own forces were likely responsible for hitting the school unintentionally.
US Defence Secretary Pete Hegseth previously said the matter was being investigated.
The strike, if a US role were to be confirmed, would amount to one of its worst single cases of civilian casualties in decades of US conflicts in the Middle East.
"The images of bombed-out classrooms and grieving parents showed clearly who pays the highest price for war: civilians with no power in the decisions that led to conflict," Türk said.
He said that "the onus is on those who carried out the attack to investigate it promptly, impartially, transparently and thoroughly".
"Senior US officials have said the strike is under investigation," he said, calling "for that process to be concluded as soon as possible, and for its findings to be made public".
Iran's Foreign Minister Abbas Araghchi said in a video address to the UN meeting in Geneva that the bombing was a "deliberate and intentional" attack by the US.
"This atrocity cannot be justified, cannot be concealed, and must not be met with silence and indifference," he said.
The letter, from nearly every Senate Democrat, asked a series of detailed questions about the strike in Minab - starting with whether the US carried it out.
Anadolu via Getty Images
It questioned whether old or faulty target analysis could have led to the school building being hit.
It also highlighted Hegseth's vow during a news conference that there would be no "stupid rules of engagement" in the war, and asks if the defence secretary had complied with rules to prevent the commission of war crimes.
The Pentagon said it would respond directly to the authors of the letter, as with all congressional correspondence.
Hegseth previously said the US did not target civilians and was investigating the issue.
The New York Times - citing individuals briefed on the US investigation - reported that officers at US Central Command (Centcom) created the target co-ordinates for the strike using outdated data provided by the Defense Intelligence Agency.
The intended target of the strike was an adjacent base belonging to Iran's Islamic Revolutionary Guard Corps (IRGC), of which the school building was formerly a part.
But news agency Reuters reported that satellite imagery from mid-2015 showed the school building was walled off from the rest of the base and appeared to have operated as a school since at least 2018, when painted murals were visible on the walls.
Expert video analysis has shown the IRGC base was hit by a Tomahawk missile - a type of US cruise missile that neither Israel nor Iran is known to possess.
A video published by Iran's semi-official Mehr news agency - which was confirmed by BBC Verify to be authentic - showed a missile in the moments before it struck the base.
Experts who saw the video said the presence of a Tomahawk missile, along with evidence the area was hit with multiple strikes, indicated that it was a US operation.
On March 17, a UN fact-finding mission opened its own investigation into the strike.
Additional reporting by Tom Bateman
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