The 22-year-old was stopped for allegedly breaking hijab rules.
The European Union has raised concerns about a woman in Iran who died after being stopped for allegedly breaking hijab rules.
Mahsa Amini, 22, was detained by Iran's morality police for "unsuitable attire" last week and later died after falling into a coma.
Her woman's death has ignited demonstrations across the country, including the capital, Tehran, where demonstrators chanted against the government and clashed with police.
The EU's foreign policy chief Josep Borrell condemned Amini's death as "unacceptable" and called on the authorities to punish those responsible.
"It is imperative the Iranian authorities ensure that the fundamental rights of their citizens are respected and that those who are subjected to any form of detention are not subjected to any form of ill-treatment," Borell added.
The acting UN High Commissioner for Human Rights, Nada Al-Nashif, also released a statement on Tuesday following a violent crackdown by Iranian security forces on protesters.
“Mahsa Amini’s tragic death and allegations of torture and ill-treatment must be promptly, impartially and effectively investigated by an independent competent authority,” Al-Nashif said.
Kurdish human rights groups claim that three people were killed on Monday when security forces opened fire on demonstrators.
Tehran's police chief, General Hossein Rahimi, rejected accusations of mistreatment and labelled her death as "an unfortunate incident" due to a heart attack. Amini's family says she had no history of heart trouble.
Iranian President Ebrahim Raissi has called for an investigation into the young woman's death.
The UN Human Rights Office said Iran's morality police have expanded their patrols in recent months, targeting women for not properly wearing the Islamic headscarf, known as hijab. It said verified videos show women being slapped in the face, struck with batons and thrown into police vans for wearing the hijab too loosely.
The hijab has been compulsory for women in Iran since the 1979 Islamic Revolution, but dozens of Iranians have taken to the streets in recent years to protest the law.
The Persian hashtag #MahsaAmini has reached over 3 million mentions on Twitter.