TEHRAN: At least 17 people have been killed as popular unrest has flared across Iran over the death in custody of Kurdish woman Mahsa Amini, while a rights group said Thursday the death toll was almost twice as high.

Amini, 22, died last week after her arrest by the Islamic republic’s feared morality police for allegedly wearing a hijab headscarf in an “improper” way, and news of her death sparked widespread outrage.

“Death to the dictator” and “Woman, life, freedom”, protesters have been heard shouting in video footage shared widely online during the biggest wave of protests to rock the country in almost three years.

The US Treasury placed the morality police on its sanctions blacklist on Thursday, holding it responsible for Amini’s death and citing the “abuse and violence against Iranian women and the violation of the rights of peaceful Iranian protestors”.

Some Iranian women have burnt their scarves and symbolically cut their hair in protest at the strict dress code, in defiant actions echoed in solidarity protests from New York to Istanbul.

The Oslo-based non-government group Iran Human Rights said at least 31 civilians had been killed in Iran’s crackdown during six nights of violence against protesters in over 30 towns and cities.

Iranians have rallied “to achieve their fundamental rights and human dignity... and the government is responding to their peaceful protest with bullets,” charged the group’s director Mahmood Amiry-Moghaddam.

Security forces have fired at crowds with birdshot and metal pellets, and also deployed tear gas and water cannon, said Amnesty International and other human rights groups.

Demonstrators have hurled stones at them, set fire to police cars and chanted anti-government slogans, the official IRNA news agency said.

On Thursday, Iranian media said three militiamen “mobilised to deal with rioters” had been stabbed or shot dead, in northwestern Tabriz, central Qazvin and northeastern Mashhad.

Unprecedented images have shown protesters defacing or burning images of supreme leader Ayatollah Ali Khamenei and late Revolutionary Guards commander Qasem Soleimani.There were fears violence could escalate further after Iran restricted internet access and blocked messaging apps including WhatsApp and Instagram, as they have done during past crackdowns.

The two apps were the most widely used in Iran after the blocking of other platforms in recent years, including Facebook, Twitter, Telegram, YouTube and TikTok.

“People in Iran are being cut off from online apps and services,” Instagram chief Adam Mosseri tweeted, adding that “we hope their right to be online will be reinstated quickly”.

Activists have said that Amini, whose Kurdish first name is Jhina, suffered a fatal blow to the head after her arrest in Tehran — a claim denied by officials, who have announced an investigation.