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. He called for the investigation process to be concluded as soon as possible and for its findings to be made public.

Iran's Foreign Minister Abbas Araghchi stated that the bombing was a deliberate and intentional attack by the US. He emphasized that this atrocity cannot be justified, cannot be concealed, and must not be met with silence and indifference.

Earlier this month, Democrats in the US Senate wrote to Hegseth demanding answers about the strike, questioning whether the US carried it out and alleging that faulty target analysis may have led to the school being hit.

Reports indicate that US Central Command utilized outdated data for the target coordinates, and the intended target was an adjacent base associated with Iran's Islamic Revolutionary Guard Corps (IRGC). However, evidence suggests the school had been marked as a civilian structure since at least 2018.

The Pentagon indicated it would respond to the inquiries from Congress, stressed that the US does not target civilians, and is committed to thoroughly investigating the incident.

As calls for accountability and justice grow louder, the UN has initiated its own fact-finding mission into this harsh civilian casualty incident.

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