Hackers backing Iran's wave of women-led protests interrupted a state TV news broadcast with an image of gun-sight crosshairs and flames over the face of supreme leader Ayatollah Ali Khamenei, in footage widely shared online on Sunday.
In other anti-regime messages, activists have spray-painted "Death to Khamenei" and "The Police are the Murderers of the People" on public billboards in Tehran.
"The blood of our youths is on your hands," read an on-screen message that flashed up briefly during the TV broadcast Saturday evening, as street protests sparked by the death of Mahsa Amini, 22, again rocked Tehran and other cities.
"Police forces used tear gas to disperse the crowds in dozens of locations in Tehran," state news agency IRNA reported, adding the demonstrators "chanted slogans and set fire to and damaged public property, including a police booth".
Anger has flared since the death of Amini on September 16, three days after the young Kurdish woman was arrested by the notorious morality police for an alleged breach of the Islamic republic's strict dress code for women.
"Join us and rise up," read another message in the TV hack claimed by the group Edalat-e Ali (Ali's Justice).
It also posted pictures of Amini and three other women killed in the crackdown that has claimed at least 95 lives according to Norway-based group Iran Human Rights.
Another 90 people were killed in Iran's far southeast, in unrest on September 30 sparked by the alleged rape of a teenage girl by a police chief in Sistan-Baluchestan province, said IHR, citing the UK-based Baluch Activists Campaign.
One Islamic Revolutionary Guards Corps member was killed Saturday in Sanandaj, Kurdistan province, and a member of the Guards' Basij paramilitary force died in Tehran from "a serious head injury following an armed attack by a mob," IRNA said -- in killings that raised the death toll among security forces to 14.
- 'So many protests' -
Iran has been torn by the biggest wave of social unrest in almost three years, which has seen protesters, including university students and even young schoolgirls chant "Woman, Life, Freedom".
"Videos coming out from Tehran indicate that there are so many protests, in every corner of the city, in small and big numbers," said US-based campaigner and journalist Omid Memarian on Twitter.
In Amini's hometown Saqez, Kurdistan, schoolgirls chanted and marched down a street swinging their hijab headscarves in the air, in videos the Hengaw rights group said were recorded on Saturday.
Gruesome footage has emerged from the state's often bloody response, spread online despite widespread internet outages and blocks on all the major social media platforms.
One video shows a man who was shot dead at the wheel of his car in Sanandaj, Kurdistan's capital, where the province's police chief, Ali Azadi, later charged he was "killed by anti-revolutionary forces".
Angry men then appear to take revenge on a member of the feared Basij militia, swarming him and beating him badly, in another widely shared video.
Yet another video clip shows a young woman said to have been shot dead in Mashhad in the country's northeast.
Many on social media said it evoked footage of Neda Agha Soltan, a young woman who became an enduring symbol of the Iranian opposition after she was shot dead at protests in 2009.
- 'Not afraid anymore' -
In the face of the violence and the online restrictions, protesters have adopted new tactics to spread their message of resistance in public spaces.
"We are not afraid anymore. We will fight," read one large banner placed on an overpass of Tehran's Modares highway, seen in images verified by AFP.
In other footage, a man with a spray can is seen altering the wording of a government billboard on the same highway from "The Police are the Servants of the People" to "The Police are the Murderers of the People".
Several water features in the Iranian capital were said to have been coloured blood-red, but the head of city’s municipality parks organisation Ali Mohamad Mokhtari said: "This information is completely false and there isn't any change in the colors of fountains in Tehran".
Iran has accused outside forces of stirring up the protests, as solidarity protests have been held in scores of cities worldwide. The United States, European Union and other governments have imposed new sanctions on Iran.
On Amini's death, Iran said Friday that a forensic investigation had found that she died as a result of a long-standing medical condition, rather than of blows to the head as claimed by activists.
Amini's father told London-based Iran International that he rejected the official report: "I saw with my own eyes that blood had come from Mahsa's ears and the back of her neck."