Iranian riot police and security forces have clashed with demonstrators in dozens of cities amid continuing protests against the death of young Iranian woman Mahsa Amini in police custody.
State television reported on Tuesday police clashed with what it called "rioters" in some cities and fired tear gas to disperse them.
Despite a growing death toll and a fierce crackdown by authorities, videos posted on Twitter showed demonstrators calling for the fall of the clerical establishment while clashing with security forces in Tehran, Tabriz, Karaj, Qom, Yazd and many other Iranian cities.
Iranian authorities have restricted Internet access in several provinces, according to Internet blockage observatory NetBlocks on Twitter and sources in Iran.
On Tuesday, a spokesperson for the UN High Commissioner for Human Rights called on Iran's rulers to "fully respect the rights to freedom of opinion, expression, peaceful assembly and association".
In a statement, Ravina Shamdasani said that reports indicated "hundreds have also been arrested, including human rights defenders, lawyers, civil society activists and at least 18 journalists".
"Thousands have joined anti-government demonstrations throughout the country over the past 11 days. Security forces have responded at times with live ammunition," the statement said.
Officials said 41 people, including members of the police and a pro-government militia, had died during the protests. But Iranian human rights groups have reported a higher toll.
The Iranian human rights group Hengaw said "18 were killed, 898 people were injured and over 1,000 Kurdish protesters have been arrested in the last ten days", estimating the figures to be higher.
"Between Monday and Friday, more than 70 women have been arrested in Iran's Kurdistan ... at least four of them are under age 18," Hengaw said on Tuesday.
Iran's judiciary has set up special courts to try "rioters", according to state media.
Social media posts, along with some activists, have called for a nationwide strike. Several university teachers, celebrities and prominent soccer players have supported the protests against Amini's death, according to statements published by them on social media.
Students in several universities have refused to participate in classes, staging protests against the widespread arrest of students and forceful encounters with security forces in universities.