Until now, the Iranian government had been largely dismissive of the alleged poisonings which started to surface in November and have left around 400 girls unwell. Martha Fairlie reports.
Iran's president has ordered a top level investigation into a series of incidents in which noxious fumes have made pupils at all-girl schools ill.
Hundreds of female students have been affected since November, with some being admitted to hospital.
Government officials initially dismissed the incidents, and have only now started to acknowledge the worrying crisis, culminating with the order from Iranian President Ebrahim Raisi, on Wednesday.
But as difficulties with obtaining verified information from the country persist, little has been confirmed about the alleged poisonings.
Here, ITV News sets out what we know so far.
When did reports start to emerge?
The first cases surfaced in late November in Qom, a city southwest of Iran's capital, Tehran.
Students at the Noor Yazdanshahr Conservatory fell ill in November and then again in December. Other cases across the country swiftly followed.
How have students been affected?
Students have complained of suffering from headaches, heart palpitations, feeling lethargic or otherwise unable to move. Some described smelling tangerines, chlorine or cleaning agents.
How many schools and students have been targeted?
Some 30 schools have been affected by the incidents, according to local media reports in Iran.
As well as Qom, cases have been reported in all-girl schools in Tehran and Boroujerd. At least one boys' school has been targeted as well.
One report claimed as many as 400 students have fallen ill during the poisonings.
One girl who was hospitalised by a suspected poisoning said she was left feeling 'very numb' and unable to walk
How has Iran's government reacted?
Initially, the country's education minister dismissed the reports as "rumours".
The incidents began to emerge during the Iranian winter - where temperatures can drop below freezing and many schools are heated by natural gas - which prompted suggestions that carbon monoxide poisoning was to blame.
Slowly, officials began taking the claims seriously, and Iran's prosecutor-general ordered an investigation, saying "there are possibilities of deliberate criminal acts". Iran's Intelligence Ministry also reportedly investigated.
Last Sunday, Iran's state-run IRNA news agency filed multiple stories with officials acknowledging the scope of the crisis.
"After several poisonings of students in Qom schools, it was found that some people wanted all schools, especially girls' schools, to be closed," IRNA quoted Younes Panahi, a deputy health minister, as saying.
Ali Reza Monadi, a national parliament member who sits on its education committee, described the poisonings as "intentional".
He said the "existence of the devil's will to prevent girls from education is a serious danger and it is considered a very bad news", adding "we have to try to find roots" of this.
Then, at a Cabinet meeting on Wednesday, President Raisi said the Interior Ministry should probe the incidents, with help from the health and intelligence ministries, and promptly released the results to the public. It was the first time he had publicly addressed the poisonings.
Who has been blamed for the suspected poisonings?
Iranian authorities have not named any suspects and at first did not link the cases.
Jamileh Kadivar, a prominent reformist lawmaker and journalist, has warned that "subversive opposition" groups could be behind the attacks.
However, she also raised the possibility of "domestic extremists" who "aim to replace the Islamic Republic with a caliphate or a Taliban-type Islamic emirate".
She cited a statement from a group calling itself "Fidayeen Velayat", which said "the study of girls is considered haram" and threatened to "spread the poisoning of girls throughout Iran" if girls' schools remain open.
Iranian officials have not acknowledged any group called Fidayeen Velayat - which roughly translates to English as "Devotees of the Guardianship".
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Another prominent reformist politician, Azar Mansouri, also linked the suspected poisoning attacks to hardline groups.
Have similar incidents happened before?
Assaults on women have happened in the past in Iran, most recently with a wave of acid attacks in 2014, around the city of Isfahan.
At the time they were believed to have been carried out by hardliners targeting women for how they dressed.
However, the right for women to attend school in Iran has never been challenged before in the more than 40 years since the 1979 Islamic Revolution.
Iran itself also has been calling on the Taliban in neighboring Afghanistan to have girls and women return to school.