The official death toll from Iran's wave of popular unrest shot up Thursday to at least 17 as popular anger flares over the death in custody of the young Kurdish woman Mahsa Amini.
However, the Oslo-based NGO Iran Human Rights said at least 31 civilians had been killed in a crackdown by the Iranian security forces in six nights of violence.
Iranians have taken to the streets "to achieve their fundamental rights and human dignity ... and the government is responding to their peaceful protest with bullets", charged its director Mahmood Amiry-Moghaddam.
Amini, a 22-year-old Kurdish woman, died last week after she had been arrested by the Islamic Republic's feared morality police for allegedly wearing a hijab headscarf in an "improper" way, sparking widespread outrage.
Protesters could be heard shouting "death to the dictator" and "woman, life, freedom" in video footage shared online, during the biggest wave of protests to rock the country in almost three years.
Among those killed in clashes have been police and militia officers, state TV reported, while overseas-based human rights groups reported many more deaths, which could not be independently verified.
Security forces have fired at crowds with birdshot and metal pellets, and also deployed tear gas and water cannon, according to Amnesty International and other human rights groups.
There were fears violence could escalate further after Iranian authorities restricted internet access and blocked messaging apps including WhatsApp and Instagram, as they have done before past crackdowns.
Some women have burnt their scarves and symbolically cut their hair in protest at the strict dress code, in defiant actions echoed in solidarity protests abroad from New York to Istanbul.
Activists have said that Amini, whose Kurdish first name is Jhina, after her detention in Tehran suffered a fatal blow to the head - a claim denied by officials, who have announced an investigation.
Iranian women on the streets of Tehran told AFP they were now more careful about their dress to avoid run-ins with the morality police.
"I'm frightened," said Nazanin, a 23-year-old nurse who asked to be identified by her first name only for safety reasons, adding she believed the morality police "shouldn't confront people at all".
US President Joe Biden in an address to the UN General Assembly on Wednesday said that "we stand with the brave citizens and the brave women of Iran who right now are demonstrating to secure their basic rights".
Iran's ultra-conservative President Ebrahim Raisi, speaking later in the same forum, complained of a "double standard" and pointed to Israeli actions in the Palestinian Territories and the deaths of indigenous women in Canada.
The protests come at a particularly sensitive time for the leadership, as the Iranian economy remains mired in a crisis largely caused by sanctions over its nuclear programme.
Unprecedented images have shown protesters defacing or burning images of Supreme Leader Ayatollah Ali Khamenei and late Revolutionary Guards commander Qassem Soleimani.
The wave of unrest "is a very significant shock, it is a societal crisis", said Iran expert David Rigoulet-Roze of the French Institute for International and Strategic Affairs.
The protests are among the most serious in Iran since November 2019 unrest sparked by a sharp rise in petrol prices. The crackdown then killed hundreds, according to Amnesty.
Demonstrators have hurled stones at security forces, set fire to police vehicles and garbage bins, and chanted anti-government slogans, the official IRNA news agency said.
On Thursday, Iranian media said three militiamen "mobilised to deal with rioters" were stabbed or shot dead in northwestern Tabriz, central Qazvin and northeastern Mashhad.
UN human rights experts condemned the "use of physical violence against women" and the "state-mandated internet disruptions", which they said were usually part of larger efforts "to stifle ... free expression ... and to curtail ongoing protests".
Iran's Fars news agency reported that "in accordance with a decision by officials, it has no longer been possible to access Instagram in Iran since (Wednesday) evening and access to WhatsApp is also disrupted".
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.
Revolutionary Guards threat
Not only is the Iranian regime clamping down, but the country's powerful Revolutionary Guards called on the judiciary on Thursday to prosecute "those who spread false news and rumours".
"We have requested the judiciary to identify those who spread false news and rumours on social media as well as on the street and who endanger the psychological safety of society and to deal with them decisively," the Guards, who have cracked down on protests in the past, said.
In a statement, the Guards also expressed sympathy with the family and relatives of Amini.
Pro-government protests are planned for Friday, Iranian media said.
"The will of the Iranian people is this: do not spare the criminals," said an editorial in the influential hardline Kayhan newspaper.
This came as the US imposed sanctions on Iran's morality police, accusing them of abuse and violence against Iranian women and of violating the rights of peaceful Iranian protesters.
The US Treasury said it had put sanctions on the chiefs of the Iranian army's ground forces and of the morality police, as well as on Iran's minister of intelligence. It said it held the morality police responsible for the death of Amini.
"Mahsa Amini was a courageous woman whose death in Morality Police custody was yet another act of brutality by the Iranian regime's security forces against its own people," Treasury Secretary Janet Yellen said in a statement.
(FRANCE 24 with AFP and REUTERS)