Amnesty International has called on authorities in Iran to “immediately and unconditionally” release a female student who was arrested after stripping to her underwear, in what the organization described as a public protest against harassment related to the strict dress code of the country.

The incident took place after the woman, who has not yet been identified, reportedly had a confrontation with members of the paramilitary Basij force who tore her headscarf and tore her clothes in Tehran’s prestigious Islamic Azad University.

Videos posted on social media appear to show the woman taking off her clothes and walking into the street in her underwear. A second video shows the woman being bundled into a car by men in plain clothes.

According to the newsletter of student media Amir Kabir, the woman was harassed by a Basij member because she was not wearing a headscarf. According to Iran’s mandatory dress code, women must wear a headscarf and loose-fitting clothing in public.

The media outlet also alleged that she was beaten during the arrest and said on Saturday that information on the woman’s condition and whereabouts was not available.

Amnesty International Iran called for an “independent and impartial” investigation into the abuse allegations.

“Iranian authorities should immediately and unconditionally release the university student who was forcibly arrested after taking off her clothes in protest against the unlawful enforcement of the mandatory head covering by security officials,” it said on social media.

“Pending her release, authorities must protect her from torture and other ill-treatment and ensure access to family and a lawyer.”

Iran’s conservative Fars news agency confirmed the incident, saying the student had worn “inappropriate clothes” and “undressed” after guards told him to adhere to the dress code.

A report citing “witnesses” said guards had spoken “calmly” to the student and denied reports that their actions had been aggressive in any way.

The incident comes more than two years after Iran was rocked by nationwide protests following the death in custody of Mahsa Amini, an Iranian Kurdish woman arrested for alleged dress code violations. The protests, in which some women challenged authorities to throw off their headscarves, were later violently curbed by authorities.

With contributions from Agence France-Presse and Reuters