A United Nations panel of experts said on Wednesday it was "deeply disturbed" by the deaths of children, after the bombing of the Shajareh Tayyebeh girls' school in southern Iran, which it said killed more than 160 children, citing reports.
The school in Minab was hit on Saturday, the first day of US and Israeli attacks on Iran.
US Secretary of State Marco Rubio said on Monday that the country's forces "would not deliberately target a school".
Israel has said it is investigating the incident.
"The Committee is alarmed by reports of strikes on civilian infrastructure, including schools and hospitals, which have injured and traumatised children, and claimed many young lives," the UN Committee on the Rights of the Child said in a statement.
Children must be protected from war, the committee added.
The UN Committee on the Rights of the Child is a body of 18 independent experts that monitors implementation of the Convention on the Rights of the Child, which protects children’s rights to education and safeguards them from violence.
On Tuesday, the UN human rights office urged what it called "the forces behind a deadly attack on a girls' school in Iran" to investigate and share insights into the incident, without saying who it believed was responsible.
Iran's ambassador to the United Nations in Geneva, Ali Bahreini, had raised the issue with UN human rights chief Volker Turk in a March 1 letter, calling the attack "unjustifiable" and "criminal".
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