More than 100 female students were apparently poisoned by gas in schools in Iran on Wednesday, local media reported. There have been a number of similar incidents since November.
The head of the hospital service told Tasnim that students from seven girls' schools in the city of Ardabil inhaled gas in the morning, and 108 of them were taken to hospital. Girls in at least three schools in Tehran have also been affected.
According to Fars, students at a secondary school in the west of the capital were poisoned by a type of spray, citing the students' parents. The same source reported that emergency services were at the scene.
Nearly 800 female students in Qom and 400 in Borujerd have been affected since the first cases were recorded in late November, a spokeswoman for the Parliamentary Health Committee, Zahraa Sheikhi, said on Wednesday.
READ: Iran investigates 'mysterious poisoning' of schoolgirls as wave spreads
The results of toxicological examinations by the Ministry of Health showed that the toxic substance used in Qom consisted mainly of nitrogen gas which is mainly used in industry or as an agricultural fertiliser.
Iranian President Ebrahim Raisi assigned Interior Minister Ahmed Wahidi to follow up on the case as soon as possible, and to inform people about the progress of the investigation in order to dispel their fears. Wahidi told reporters that the authorities were still investigating those "potentially responsible" for the poisonings, but that no one has been arrested so far.
The incidents have sparked outrage in the country, and the authorities have been criticized for their silence on the increasing number of schools involved. The Ministry of Health said on Sunday that "some individuals" are doing this to "close all schools, especially girls' schools." Compulsory education is in place in Iran, and the majority of university students are women.