Younes Panahi said on Sunday as quoted by Iran International: "It was found that some people wanted all schools, especially girls' schools, to be closed."

"It has been revealed that the chemical compounds used to poison students are not war chemicals, and the poisoned students do not need aggressive treatment, and a large percentage of the chemical agents used are treatable," he told a press conference as quoted by the website.

Majid Monemi, the deputy governor of Lorestan, told Iran International that 50 female students of a high school in Borujerd, western Iran, were poisoned again.

According to reports, serial poisoning of students in the country started in Qom in December and then spread to several other cities.

The government has not determined the cause of the poisonings, but some local media say it could be the work of religious zealots who want to prevent girls from attending school, reports the website.

Iran witnessed a series of protests last year, where a large number of women had participated, following the death in custody of 22-year-old Iranian Kurd Mahsa Amini for an alleged violation of the country’s strict dress code for women.