A young Iranian woman has died after being arrested by the vice squad.
According to police, 22-year-old Mahsa Amini suffered a heart attack after her arrest and fell into a coma.
She died in hospital on Friday, state television reported.
Police confirmed the 22-year-old's death and said there was no "physical contact" between her and the police officers.
However, the exact circumstances of her death are unclear.
Amini was arrested in Tehran on Tuesday by the Vice Police, who are responsible for enforcing strict dress codes for women.
According to police, the 22-year-old was taken to a police station along with other women for "wearing inappropriate clothing" to be briefed on the dress code.
There she "suddenly passed out" in a meeting room and was taken to the hospital.
allegations of torture and ill-treatment
What exactly happened between her arrival at the station and her admission to the hospital is unclear.
According to the broadcaster 1500tavsir, which reports on human rights abuses in Iran, she suffered a blow to the head.
The human rights organization Amnesty International reported that there were "allegations of torture and other ill-treatment in custody" and called for an investigation into the circumstances of the young woman's "suspicious" death.
Amini's body was taken to the coroner's office, according to state television.
Before the death became known, Iranian President Ebrahim Raisi announced that he had commissioned the interior minister to investigate the case.
The moral police, which monitors compliance with the headscarf requirement and other rules on Iran's streets, has recently come under increasing criticism.
Since shortly after the 1979 Islamic revolution, women of all nationalities and beliefs have been required to cover their hair in public.
In the past two decades, however, many women in Tehran and other major cities have taken the rules lightly, allowing strands or more of their hair to peek out of their veils.