The organization also called on the UN’s fact-finding mission in the country to focus on state acts of violence in “minority-dominant” regions such as Kurdistan, and Sistan and Baluchistan where the massacre took place in its provincial capital.

And it urged the need for Iran to respect the UN Basic Principles on the Use of Force and Firearms by Law Enforcement Officials.

The group noted that it had assessed 52 videos and images provided by Iranian human rights group Haalvsh, and collated witness testimony, to determine that at least 12 people were killed in Zahedan on Sept. 30, including a young boy.

Thirty people were injured, and HRW said at least eight more had been killed in the city in the days afterwards, including a further three children.

Balochi human rights groups in the area, meanwhile, put the death toll as high as 97 between Sept. 30 and Oct. 5, including nine children.

The deaths center around security forces opening fire on protesters from rooftops surrounding the city’s Grand Mosalla prayer hall as a large group of demonstrators made its way toward a local police station, and later at the city’s largest Sunni mosque as the dead and injured were taken to it.

Protesters responded with stones and Molotov cocktails, and many bystanders were caught between the two sides, HRW added.

At least four members of Iran’s Islamic Revolutionary Guard Corps were killed by protesters responding to the attack.

One witness told HRW: “As I came out (of the prayer hall) to look for my brother, I saw bodies on the ground, mostly young people. At first, I didn’t even realize the police were shooting but then I noticed that they were firing from the buildings.”

Another witness, Ismael Shahbakhsh, told HRW he had gone to a local hospital searching for his nephew.

He said: “When I entered the emergency room, I saw a distressing scene that is impossible to describe.

“The white ceramic tiles of the floor had turned red … I looked through three pages of 10 to 15 names of those injured and Farzad’s name was not there … Afterward a nurse came to me with five or six pages, each with 18 to 20 names on it, and told me Farzad was among those who died.”

State-affiliated news agency Tasnim News later claimed armed organization Jaish Al-Adl was responsible for the violence, which it labeled “terror attacks.” The group has since denied the accusations.

Prominent local imam, Mowlana Abdol Hamid Ismaeelzahi, told HRW: “It’s the police station that first starts shooting, shooting indiscriminately, and shooting military ammunition, not only toward the place where those youngsters were chanting and expressing their feelings, but also even toward inside the Grand Mosalla, where people were praying.

“They shoot there and throw teargas inside, even the women’s section gets gassed and is shot at, and one of the women is killed, is martyred, as well.”

On Oct. 28 local authorities announced that six members of the security forces had been killed in Zahedan during the clashes, as well as 35 protesters and members of the public, blaming “negligence” for the deaths of innocent worshippers and dismissing the local police chief.

That same day, HRW said, authorities killed two children during protests in the city, a 13-year-old and 16-year-old, who were both shot in the head.

Protests have engulfed Iran since the death of 22-year-old Kurdish woman Mahsa Amini at the hands of the country’s morality police in September, after she was accused of wearing her hijab improperly.

Hundreds of people have been killed throughout the country by government forces, and thousands more arrested, with some of those detained executed by the regime, and many more facing death or long, punitive prison sentences, as well as widespread reports of torture and other forms of mistreatment while in detention.

As of Dec. 9, HRW said it had evidence for the deaths of at least 255 people, with another 226 under investigation.

It added that it had further evidence of “handguns, shotguns, and military assault rifles” being used against protesters “during largely peaceful and often crowded demonstrations in at least 13 cities across the country,” with most of the lethal force reserved for the country’s ethnic minority-led regions.

The events of Sept. 30 in Zahedan were the bloodiest in Iran this year, according to HRW’s senior Iran researcher, Tara Sepehri Far.

She said: “The number of protesters and bystanders shot by Iran’s security forces on ‘Bloody Friday’ was the largest killed in a single day during the protests, but no one responsible has been arrested.

“The government’s immense brutality has brought the struggles of long-neglected communities like Zahedan to the center of protests.”