Former Iranian prisoners of conscience have told the BBC that they were filmed during strip searches in prisons.

They also said some detainees were forced to remove their sanitary pad or tampon during their period and squat or squat jump.

“They do this to humiliate us,” Mozhgan Keshavarz, who spent nearly three years behind bars, mostly in notorious Evin and Qarchak prison in Tehran province, told the BBC.

She said she experienced three strip searches in front of security cameras during her incarceration, which ended in January 2022.

The third time, a female prison guard took photographs of her naked, she said. When Ms Keshavarz protested, she was told it was necessary to counter future claims of torture.

“Who would see these videos and pictures? Would the regime use them later to silence us?” she asked, referring to the risk of being blackmailed even when her sentence was over.

Ms Keshavarz is a women’s rights activist who has protested against the mandatory hijab, or headscarf.

Her Instagram account features a series of artistic images of her without a hijab in a variety of public places.

She was accused of “conspiracy against national security, disrespecting Islam, propaganda against the Islamic Republic of Iran, and promoting corruption and obscenity” and sentenced to 12 years and seven months in prison.

More recently, she has been sentenced for “corruption on Earth” – a crime which carries the death penalty – and now lives in exile, from where she spoke to the BBC.

Women prisoners have told the BBC that it has long been common practice to strip search drug-related detainees in Iran to look for hidden narcotics. But prisoners of conscience had not previously been typically subjected to it, and certainly not in front of the camera.

In early June, Iran’s judiciary denied the allegations of filming prisoners, dismissing them as “hybrid warfare and full-scale Western propaganda against Iran”.

However, in mid-June, the head of the judiciary committee in the Iranian parliament said “only the female guards watch the footage of female prisoners” – in doing so acknowledging that women prisoners are filmed.

It is also alleged that the filming happens in areas where there should not be any cameras.

“According to prison regulations, CCTV is allowed only where prisoners are in motion, like in corridors,” Mohammad Hossein Aghassi, a practising lawyer in Tehran, told the BBC.

The practice of filming strip searches is not unique to Iran – there have been incidents in other countries such as a well-publicised case in the Australian state of New South Wales.

Documents obtained under a freedom of information request revealed that officers routinely filmed searches while they were being conducted.

What is different – and disturbing – about Iran is that our interviewees and many others allege a systematic, intentional practice designed to humiliate the detainees.

The BBC has obtained confidential documents from a hacking group called Edaalat Ali, dated November 2021, which contain a letter from the Iranian Judiciary acknowledging one such case of strip searching.

The letter specifically mentions Mojgan Kavoosi, a rights activist for the Kurdish ethnic minority, who was subjected to this practice in a prison in the city of Karaj.

A source from within Iran who is familiar with the case told the BBC that Ms Kavoosi was subjected to strip searches on five occasions.

The documents show that after Hrana, a human rights news agency, published a report about her strip search, Iran’s prosecutors’ office was asked to conduct an investigation into the matter.

Ms Kavoosi is now free on bail.

Elaheh Ejbari, a rights activist for the Baluch ethnic minority, who now lives in exile, told the BBC that officials “mocked my body during the strip searches both times I was arrested”.

She also showed us a scar on her hand, saying her interrogator had stubbed a cigarette out on her skin.

Ms Ejbari was first arrested in September 2020 in Tehran on charges of “propaganda against the Islamic Republic of Iran” and spent six weeks in Evin prison. She was arrested a second time in November 2022 and was kept in an unknown location for three days.

After receiving persistent calls from security forces threatening her arrest, she fled Iran.

Nasibe Shamsaei is another Iranian women’s rights activist who says she endured strip searches three times.

She is one of the Girls of Revolution Street, a group who protested against the compulsory hijab in Iran in 2018 by public removing their headscarves. Dozens were arrested at the time.

Accused of a number of crimes including “propaganda against the Islamic Republic of Iran by removing hijab in public and disrespecting the founder of Islamic Republic of Iran and the Supreme Leader”, Ms Shamsaei was sentenced to 12 years in prison.

She was released after almost three months in Qarchak prison, and now lives in exile.

She recalls that when she complained about being exposed in front of CCTV cameras, a prison guard responded: “From now on, everything is possible.”