Iran’s president on Wednesday ordered authorities to investigate a series of incidents in which noxious fumes have sickened students at girls’ schools, which some officials suspect are attacks targeting women’s education.

Hundreds of girls at around 30 schools have been sickened since November, with some winding up in hospital beds. Officials initially dismissed the incidents, only acknowledging the scope of the crisis in recent days.

Children have complained about headaches, heart palpitations, feeling lethargic or otherwise unable to move. Some described smelling tangerines, chlorine or cleaning agents.

Unlike neighboring Afghanistan, Iran has no history of religious extremists targeting girls’ education. Women and girls continued attending school even at the height of the 1979 Islamic Revolution that toppled Iran’s Western-backed monarchy.

At a Cabinet meeting on Wednesday, President Ebrahim Raisi said the Interior Ministry should probe the incidents, with help from the health and intelligence ministries, and promptly release the results to the public, the state-run IRNA news agency reported.

It was the first time he has publicly addressed the poisonings.

The night before the Cabinet meeting, a senior security official had downplayed the matter, dismissing it as psychological warfare by unnamed enemies of the country.

“Over 99% of this is caused by stress, rumor and psychological war started particularly by hostile TV channels, to create a troubled and stressful situation for students and their parents,” the deputy interior minister, Majid Mirahmadi, told state TV. “Their goal was to force schools to close.”

The poisonings come at a sensitive time for Iran, which has faced months of nationwide protests since a young woman died in September after being arrested by the morality police for allegedly violating Iran’s strict Islamic dress code.

After months of downplaying the poisonings, state-run IRNA filed multiple stories on the subject on Sunday in which officials acknowledged the scope of the incidents.

Iran’s prosecutor-general has ordered an investigation, saying “there are possibilities of deliberate criminal acts.” IRNA quoted a deputy health minister as saying that unnamed people wanted the schools to close.

Suspected extremists attacked women with acid for not dressing conservatively enough around the Iranian city of Isfahan in 2014. But there’s no opposition to women’s education in Shiite Islam, and Iran has even called on the Taliban in Afghanistan to let women and girls return to school.