The United States and Israeli air strikes on a girls’ elementary school in Minab in southern Iran have left more than 150 girls dead, reported 24NewsHD TV Channel on Sunday.
Visuals have emerged of crowds of people searching through the rubble in search of survivors.
Iran's ambassador to the United Nations has accused the US and Israel of targeting the school and public places.
"Hundreds of civilians have been killed and injured [as a result of] the aggression and atrocious crime of the United States regime and the Israeli regime, and the deliberate … targeting of civilian infrastructure," Amir-Saeid Iravani has told an emergency meeting of the UN Security Council.
"The number of innocent civilians continues to rise. This is not only an act of aggression, it is a war crime, and a crime against humanity.
"The aggressors have also targeted a school in the city of Minab … killing more than 100 children."
What appeared to be scorch marks were visible on the walls of what remained of the building, and most of the glass windows were broken.
Iranian Foreign Minister Abbas Araghchi has said "dozens of innocent children have been murdered", in a post on social media.
"The destroyed building is a primary school for girls in the south of Iran. It was bombed in broad daylight, when packed with young pupils," Araghchi said.
"Dozens of innocent children have been murdered at this site alone. These crimes against the Iranian people will not go unanswered."
The US Central Command has said that reports of civilian deaths and casualties are being reviewed and that the protection and safety of civilians is a top priority.
The Central Command has further said that measures will be taken so that there could be less collateral damage.