Iran is facing global criticism and calls to properly investigate the death of a 22-year-old woman who had been held in custody by Iran’s morality police for improperly wearing her hijab, or headscarf. The incident has sparked days of protests that have turned deadly in Iran. Nada Al-Nashif, the acting U.N. high commissioner for human rights, said Tuesday, "Mahsa Amini's tragic death and allegations of torture and ill-treatment must be promptly, impartially and effectively investigated by an independent competent authority.” Amini was detained last week by Iranian authorities and taken to a police station where she collapsed. She died three days later. Iranian police say she died of a heart attack and have denied mistreating her. Authorities say they are investigating the incident, but widespread protests against Amini’s detention and death have erupted throughout much of Iran, with three deaths linked to the unrest. U.S. Secretary of State Antony Blinken said Tuesday that Amini "should be alive today." "Instead, the United States and the Iranian people mourn her,” the top U.S. diplomat said on Twitter. “We call on the Iranian government to end its systemic persecution of women and to allow peaceful protest.” Iranian Foreign Minister Hossein Amirabdollahian rejected the criticism of authorities’ handling of the case, accusing the United States of "shedding crocodile tears." "An investigation was ordered into (the) tragic death of Mahsa, who, as (President Ebrahim Raisi) said, was just like our own daughters," he tweeted. "To Iran, human rights are of inherent value — unlike those who see it (as) a tool against adversaries." During his speech to the U.N. General Assembly Wednesday, U.S. President Joe Biden said, “Today, we stand with the brave citizens, the brave women of Iran, who right now are demonstrating to secure their basic rights.” Italy's Foreign Ministry called for "the perpetrators of this cowardly act" against Amini to be held to account, saying "violence against innocent people, especially women and girls, can never be tolerated." British Foreign Office Minister Tariq Ahmad tweeted Wednesday, “We urge the Iranian government to investigate the circumstances of her death with rigor and transparency, and to hold to account anyone responsible." "We call on Iran to respect the right to peaceful assembly, to exercise restraint and to release unfairly detained protesters," Ahmad said. Some material in this report came from The Associated Press and Reuters.