The non-governmental organization Reporters Without Borders (RSF) called on Wednesday for the release of a journalist arrested for covering the wave of mysterious poisonings of schoolgirls in Iran, denouncing a wider crackdown on the media.

“Ali Pourtabatabei must be released unconditionally. The systematic repression against journalists who continue to dare to do their work must stop,” said Jonathan Dugger, head of RSF’s Middle East department, in a press release from the NGO.

Since November, some 5,000 schoolgirls have been poisoned, according to Iranian authorities.

A case that further escalated the tension in the Islamic Republic, which has been shaken since September by mass protests triggered by the death at the hands of the morality police of Mahsha Amini, a young Iranian of Kurdish origin, who was arrested for violating the strict dress code imposed on women in Iran .

“As they already did with the journalists who exposed the Mahsha Amini case, the Iranian authorities are trying to silence those who dare to investigate and publish information that embarrasses the regime,” Mr. Dagger underlined.

According to RSF’s Middle East regional officer, thirty-one journalists and media professionals are currently in prisons in Iran, most of them arrested as part of the crackdown on the dissent movement.

According to the NGO, Ali Pourtabatabei began covering the case from the first poisoning, at the end of November in the city of Qom (southwest of Tehran). He continued to cover the developments until his arrest on 5 March.

Human rights NGOs have accused authorities of failing to protect girls’ right to education in Iran, sparking protests on Monday and Tuesday.

Supreme Leader Ayatollah Ali Khamenei said on Monday that the perpetrators of these “unforgivable crimes” would be hunted down and punished “mercilessly”.

RSF noted that the journalist was able to call his sister and tell her he was being arrested, but where he is being held is unknown.

Iran’s interior ministry announced on Tuesday that “a number of people” allegedly manufacturing dangerous substances were arrested in ten provinces, including the father of a schoolgirl.