Iranian media reports say Supreme Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei has urged officials in the country to investigate the alleged poisonings of school girls with utmost seriousness.

Speaking on the sidelines of a ceremony to mark the National Tree Planting Day, Ayatollah Khamenei on March 6 described the poisonings as a heinous and unforgivable crime.

"If the cases of poisoning of students are proven, perpetrators should face maximum punishment with no pardon," he said, according to IRNA.

Tasnim news agency reports that Ayatollah Khamenei further called the incident “a crime against the most innocent members of the society, namely children, and a source of psychological insecurity in the society and concern for the affected families.”

Earlier, Iranian President Ebrahim Raisi issued strict orders for pursuing the issue of poisonings in schools.

Raisi said the poisonings are a new plot by Iran's enemies as he described them as an inhumane crime.

"This move is another ring in the chain of the enemy's plots aimed at creating tension in the society, disturbing the public opinion and horrifying the offspring of this land and territory, and its roots need to be identified and seriously dealt with," President Raisi noted.

Wave of suspected poison attacks on schoolgirls has sparked protests in Iran.  Worried parents protested in Iran’s capital Tehran and other cities on March 4 over a wave of suspected poison attacks that have affected schoolgirls in dozens of schools, according to Iranian news agencies and social media videos.

The unexplained illnesses have reportedly affected hundreds of schoolgirls in recent months.

Chain poisoning in girls' schools in Iran is a series of alleged successive chemical attacks during which students of dozens of schools in Iran have been poisoned in a suspicious manner.  These events reportedly started on November 30, 2022, in a girls' high school in Qom.

Activists say the poisonous attacks have been deliberately carried out by hardline religious groups opposed to girls' education in an attempt to force schools to shut.