Rights groups fear up to 10 people, including children, were killed on Friday as protests rocked a flashpoint province in Iran's south-east.
Security forces opened fire on protesters in various places across Sistan and Baluchestan province, which borders Afghanistan and Pakistan. The region, home to the marginalised Baloch people, has seen some of the bloodiest violence since protests began more than six weeks ago over the death of Mahsa Amini.
More than 90 people were killed in a single day in September — referred to as Zahedan's Bloody Friday — after protesters gathered in the province's main city to condemn the alleged rape of a 15-year-old girl by a local police chief.
Security forces on Friday afternoon began firing live ammunition from the rooftops of the governor's office and other official buildings in the city of Khash, according to Amnesty International.
Videos shared by protest groups showed plumes of smoke rising after protesters set fire to police stations in the province.
The rights group said it was "gravely concerned" there would be further bloodshed amid widespread internet blackouts and reports of additional security forces deployed to the province.
A 14-year-old was among the dead as authorities shot "with the intent to kill", said a Baloch activist group based in London.
Hospitals were overwhelmed with the number of injured, it added.
Footage on social media showed a slain protester who appeared to be in his 20s left on a blood-stained street before being whisked away by authorities. Another video, which could not be verified, showed security forces firing at young schoolboys as they ran away from authorities.
Others shared images of the bloodied corpses of teenagers and young men killed during the protests.
More than 200 people are estimated to have been killed by security forces since protests began, sparked by Amini's death in morality police custody. They quickly spread to every province in the country, with young and old calling for an end to the regime which was ruled since 1979.
Islamic Revolutionary Guard Corps and Basiji forces have led the ruthless crackdown on crowds and bystanders, with some of those killed shot while watching the protests from their homes.
Young protesters have circulated advice online to try and lessen their injuries, calling on others to place yoga mats and life vests under their clothing before taking to the streets. Doctors abroad have said they have received calls from injured protesters pleading for help from inside Iran, fearing arrest if they go to hospital.
A prominent cleric in Zahedan reportedly called on Friday for authorities to hold a referendum on the people's demands, while condemning the violence against protesters.
Molavi Abdolhamid, a top Sunni cleric and leader of Friday prayers in the city, said authorities "cannot beat back a nation" by "killing, beating and arresting".
Some religious leaders, particularly in minority areas, have been vocal in their support of protesters.
Footage shared by protesters in western Kurdish areas has shown mosques and their imams playing Kurdish revolutionary songs as demonstrators gathered in the streets last week.