A wave of illnesses at girls' schools under mysterious circumstances has prompted many Iranians to pour into city streets across the country to call for the government to step down as speculation grows that the crisis was brought about by officials who have been slow to react.
Protesters in Tehran's Naziabad neighborhood and others in the capital chanted "Death to the child-murdering government!" and "Death to the dictator," a reference to Supreme Leader Ayatollah Ali Khamenei, from windows and rooftops as reports of illness continued to surface.
The first incident is believed to have occurred in November, when 18 schoolgirls in the city of Qom were taken to a hospital after complaining of symptoms that included nausea, headaches, coughing, breathing difficulties, heart palpitations, and numbness and pain in their hands or legs.
Since then, hundreds of more cases have occurred and it remains unclear what may be causing the illnesses, though some of those affected have said they smelled chlorine or cleaning agents, while others said they thought they smelled tangerines in the air.
Videos published on social media from the northwestern city of Ardabil also show anti-government slogans being chanted by protesters in several neighborhoods.
According to Ali Mohammadian, president of Ardabil University of Medical Sciences, female students in 11 schools in Ardabil fell ill on March 1 after reporting that they smelled gas. Dozens were taken to hospital.
"About 343 students in total have been discharged from the hospital and 5 percent of those who were admitted had more severe symptoms and are under hospital care," Mohammadian told the semiofficial Mehrnews agency.
The slow response by authorities has prompted some to accuse the government of purposely "poisoning" students, who have been at the forefront of recent anti-government protests -- the biggest threat to the Islamic leadership since the 1979 revolution.
Iran has been roiled by unrest since the September 16 death of 22-year-old Mahsa Amini while in police custody for allegedly wearing a hijab, or head scarf, improperly.
The government has held several counterrallies to try to quell the dissent, but people continue to take to the streets across the country, as universities and schools have become leading venues for clashes between protesters and the authorities.
Security forces have also launched a series of raids on schools across the country, violently arresting students, especially female students, who have defiantly taken off their hijabs in protest.