Hundreds of angry demonstrators have been arrested with crowds taking to the streets of major cities across Iran for eight straight nights since the death of Mahsa Amini.
The 22-year-old Kurd was pronounced dead after spending three days in a coma following her arrest by Iran's feared morality police for wearing the hijab headscarf in an "improper" way.
State television said the number of deaths in "recent riots" had risen to 35, up from 17 previously, including at least five security personnel.
Sweeping arrests have been reported, with the police chief in the northwestern province of Guilan announcing Saturday "the arrest of 739 rioters including 60 women" in his region alone, Tasnim news agency said.
Protests were held around the Islamic republic on Friday night, with online videos showing some turning violent, including in Tehran.
Footage showed security forces firing what appeared to be live ammunition at unarmed demonstrators in the northwestern cities of Piranshahr, Mahabad and Urmia.
In a video shared by the Oslo-based Iran Human Rights non-governmental organisation, a uniformed member of the security forces is seen shooting an AK-47 assault rifle at protesters in Shahr-e Rey, on Tehran's southern outskirts.
Security forces have carried out a wave of arrests of activists and journalists, with Sherif Mansour of US-based media watchdog the Committee to Protect Journalists (CPJ) reporting 11 had been detained since Monday.
They include Niloufar Hamedi of the reformist newspaper Shargh, who reported on Amini's death.
Elsewhere, the Norway-based Kurdish rights group Hengaw said protesters "took control" of parts of the city of Oshnaviyeh, in West Azerbaijan province.
Images showed protesters walking freely with their hands aloft in triumph, but Hengaw acknowledged this could be "temporary" and expressed fears of a new crackdown there.
Amnesty International warned of "the risk of further bloodshed amid a deliberately imposed internet blackout".
The London-based human rights group said evidence it gathered from 20 cities across Iran pointed to "a harrowing pattern of Iranian security forces deliberately and unlawfully firing live ammunition at protesters".
In its statement, Amnesty said security forces had shot dead at least 19 people on Wednesday night alone, including at least three children.
Thousands of people marched through Tehran during a pro-hijab rally Friday, paying tribute to security forces who have moved to quell a week of protests by what media called "conspirators".
Demonstrations in support of the security forces also took place in the cities of Ahvaz, Isfahan, Qom and Tabriz.
Amini died following her arrest by Iran's morality police, a unit responsible for enforcing the Islamic republic's strict dress code for women.
Activists said she suffered a blow to the head in custody but this has not been confirmed by the Iranian authorities, who have opened an investigation.
Iranian women have burnt their headscarves and symbolically cut their hair in protest at the strict dress code, echoed in solidarity demonstrations from New York to Istanbul and Brussels to Santiago, Chile.
Iran's Interior Minister Ahmad Vahidi insisted Amini had not been beaten.
"Reports from oversight bodies were received, witnesses were interviewed, videos were reviewed, forensic opinions were obtained and it was found that there had been no beating," he said.
The minister said Iran was investigating Amini's death, adding "we must wait for the final opinion of the medical examiner, which takes time".
Amnesty dismissed the Iranian probe and called on the world to take "meaningful action" against the bloody crackdown.
"UN member states must go beyond toothless statements, hear the cries for justice from victims and human rights defenders in Iran and urgently set up an independent UN investigative mechanism," said Heba Morayef, its director for the Middle East and North Africa.
Iran has imposed tough restrictions on the use of the internet in a bid to hamper protesters gathering and stop the flow of images of the backlash from reaching the outside world.
The United States announced Friday it was easing export restrictions on Iran to expand internet services.
The new measures would "help counter the Iranian government's efforts to surveil and censor its citizens," said Secretary of State Antony Blinken.