Images from state media show rows of freshly dug graves and a large crowd of mourners following a funeral procession in the city of Minab on Tuesday.
According to Iranian authorities, more than 160 people - most of them children - were killed in the attack on the Shajareh Tayyebeh girls' school on Saturday morning. The Iranian government points to Israel and the United States as responsible.
The death toll, or who fired the specific rocket, has not been independently confirmed by international media.
But videos and images verified by The New York Times show that at least half of the two-story school building was destroyed in the explosion. Schoolbooks and bloodstained school bags are visible among the rubble as distraught relatives search the wreckage. Another video from the scene shows victims lined up in black body bags.
“Serious crime”
The Guardian , which has also verified several videos and images from the incident, states that the explosion occurred sometime between 10 and 10:45 a.m. Saturday - just as the U.S. and Israel began bombing Iran.
The school week in Iran runs from Saturday to Thursday, which means that students and teachers were likely present at the time of the explosion.
The UN agency UNESCO condemns the attack and expresses "deep concern" about the effects of the war.
"Killing students in a place intended for learning constitutes a serious violation of international humanitarian law," UNESCO wrote in a statement .
Next to military buildings
Pir Hossein Kolivand, head of the Iranian Red Crescent, says in a video statement that the school attack is "unprecedented" and that "not even in Gaza" have so many students been killed in a single attack.
The school building is located next to a number of buildings belonging to Iran's Revolutionary Guard. However, the school is separated from the military complex by a wall, according to The Guardian and The New York Times. Judging by the videos from the scene, the military buildings also appear to have been hit in attacks on Saturday.
When asked by the BBC this weekend whether the US might have been behind the school attack, Senator Marco Rubio responded that "the US would not knowingly attack a school", and that the country's War Department "will investigate it if it was our attack".
Israel has not commented on the incident.
