At least 35 people have been killed in more than a week of protests in Iran, a state-affiliated news agency reported late on Friday, as people came out to the streets again to voice anger over the death of a young woman in police custody.
The official death toll had stood at 17, including five security personnel, but human rights groups say at least 50 people have been killed as security forces try to quell the protests.
"The number of people who died in recent riots in the country has risen to 35 people," the Borna news agency, which is affiliated to the sports ministry, said.
Hundreds of people have been arrested, including more than 700 people in the province of Guilan, according to Tasnim news agency.
Gen Azizollah Maleki, the police chief of Guilan, on Saturday announced "the arrest of 739 rioters including 60 women" during the week, the Iranian media outlet said.
Demonstrators have taken to the streets of major cities across Iran, including Tehran, for eight straight nights since the death of Mahsa Amini.
The 22-year-old Kurdish woman was pronounced dead after three days in a coma following her arrest by morality police in the Iranian capital for wearing the hijab headscarf in an "improper" way.
President Ebrahim Raisi said Iran must "deal decisively with those who oppose the country's security and tranquility", state media reported.
He was speaking by telephone on Saturday to the family of a member of the Basij militia killed while taking part in the crackdown on unrest in the north-eastern city of Mashhad, the reports said.
Mr Raisi returned to Iran on Friday evening after attending the UN General Assembly in New York, where he told reporters that Amini's death would be investigated "steadfastly".
Iranian authorities have claimed Amini suffered from health conditions that led to her death from a heart attack, but activists say she suffered a blow to the head while in custody.
On Friday night, Interior Minister Ahmad Vahidi said investigations showed that 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," Mr Vahidi was quoted as saying by Iranian media.
"We must wait for the final opinion of the medical examiner, which takes time," he said.
Protests over Amini's death have spread to to cities across the country, including Isfahan, Mashhad, Shiraz and Tabriz, as well as in her native Kurdistan province.
Demonstrators have hurled stones at security forces, set fire to police cars and chanted anti-government slogans, state news agency IRNA reported.
The New York-based Centre for Human Rights in Iran said the government responded with "live ammunition, pellet guns and tear gas, according to videos shared on social media that have also shown protesters bleeding profusely".
Iran Human Rights, based in Olso, said 50 protesters had been killed as of Friday.
Demonstrators clashed with security forces on Friday evening in the city of Bokan in West Azerbaijan province, the organisation said. The report could not be independently verified.
In the city of Babol, in northern Mazandaran province, demonstrators were seen setting ablaze a large billboard bearing the image of Iran's supreme leader Ayatollah Ali Khamenei, in videos shared online.
Unverified footage appeared to show protesters setting fire to a base of the Basij militia on Ferdowsi Street in downtown Terhan. It could not immediately be verified.
Some women demonstrators have defiantly taken off their hijabs and burned them in bonfires or symbolically cut their hair before cheering crowds, video footage spread virally on social media has shown.
Internet access has been restricted in what web monitor NetBlocks has called a "curfew-style pattern of disruptions".
"Online platforms remained restricted and connectivity is intermittent for many users and mobile internet was disrupted for a third day on Friday," NetBlocks said.
Measures were taken in response to "the actions carried out via these social networks by counter-revolutionaries against national security", Iran's Fars news agency said.
The US on Friday said it was easing restrictions to allow technology companies to offer Iranians access to secure platforms and services after Tehran shut down access to WhatsApp and Instagram – two of the most widely used social media platforms in the country – on Wednesday.