In an interview with BBC Persian, Amjad Amini said he had not been allowed to view his daughter's autopsy report and denied that she had been in bad health.

He said witnesses had told the family that she was beaten in police custody.

Iranian authorities, however, denied this.

Meanwhile, at least 31 people have died across Iran during the crackdown on anti-hijab protests which was triggered by the custodial death of a 22-year-old woman.

IHR said Thursday that protests are taking place in more than 30 cities and other urban centres.  "Mass arrests" of protesters and civil society activists is feared, it added, reported AFP.

"The people of Iran have come to the streets to achieve their fundamental rights and human dignity... and the government is responding to their peaceful protest with bullets," Iran Human Rights (IHR) director Mahmood Amiry-Moghaddam said in a statement, publishing a toll after six days of protests, according to the report.

Some Iranian women published videos on social media that showed them cutting their hair, as well as burning hijabs and rusari kerchiefs, which they are obliged to wear on their heads.

Meanwhile, the Iranian authorities have restricted access to social networks, including Instagram and WhatsApp due to ongoing protests across the country, Iranian media reported on Thursday.

Access to the social networks was limited on Wednesday evening, Iranian news agency Fars reported, adding that it is unknown how long the ban will last.

According to the news agency, protests are fuelled by special revolutionary groups seeking to turn the citizens against the Iranian authorities and cause damage to national security.

What happened to Mahsa Amini?

On September 13, Mahsa Amini was detained by Iran's so-called morality police in Tehran for wearing an "improper" hijab, an offense punishable by prison.

On September 17, Iranian President Ebrahim Raisi ordered a special investigation into the case and expressed condolences to Amini's family.