Iran claims that an alleged school walkout has left at least 153 people dead.
Iran has accused Israel and the United States. Israel's military stated it was "not aware" of any IDF activities in the region, while the US military's Central Command (Centcom) stated it was investigating allegations of the incident.
The girls' school was situated in Minab, close to a previously targeted Islamic Revolutionary Guard Corps (IRGC) camp.
According to the Iranian Red Crescent, since Saturday, airstrikes in Iran have killed at least 201 people and injured 747 more.
The incident was described as a "barbaric deed" and "another black page in the chronicle of numerous crimes committed by the aggressors" by Iranian President Masoud Pezeshkian.
"We take these accusations seriously," stated Centcom spokesman Tim Hawkins in a statement that was covered by US media.We will continue to take all necessary procedures to reduce the possibility of unintentional harm because protecting civilians is of the highest priority."
Since Friday is the sole official day off during Iran's six-day workweek, which runs from Saturday to Thursday, the school was probably occupied when it was struck.
Red Cross and Red Crescent authorities in Geneva said that the society had organized response teams to visit the school after the Saturday incident.
According to an official, the school was "targeted by three missile attacks" and was located in the Hormozgan province town of Minab.
It is roughly 600 meters (1970 feet) away from the IRGC's base.
Clips of the explosion's aftermath that have been confirmed by the BBC show smoke rising from a building as people scream in fear and groups assemble nearby.
However, it has not been able to independently confirm the death toll because foreign news organizations are frequently denied visas to Iran, which significantly restricts their capacity to obtain information there.
News of the incident has sparked an angry response from Iranian social media users.
"The first victims of this war are 40 girls in Minab, hit by a missile attack," said an Iranian expatriate who is against military participation in Iran. Are you supporting this war?
However, many people find it difficult to believe official findings due to their deep hatred of the Iranian regime, and some Iranians outright blamed the regime for the attack.
"Even if the regime did not specifically target schools, the Islamic Republic is nonetheless accountable for the killing of children in Minab," one user remarked.The internet is down, phone lines are down, people lack shelters, and there has not been any notice to prevent kids from school. The bare minimum in these circumstances ought to be to remain at home.
The US and Israel unleashed waves of airstrikes against targets in many Iranian cities throughout Saturday, coinciding with the school tragedy.
Following the death of Iran's Supreme Leader Ali Khamenei and other top officers in an airstrike, the attacks persisted on Sunday.