Warning: this story contains graphic content which some readers might find distressing

Hundreds of photos revealing the faces of those killed during Iran’s violent crackdown on anti-government protests have been leaked to BBC Verify.

The pictures, which are too graphic to show without blurring, reveal the bloodied, swollen and bruised faces of at least 326 victims – including 18 women. The images, displayed in a south Tehran mortuary, are one of the only ways families have been able to identify their dead loved ones.

Many of the victims were too disfigured to be identified, and 69 people had been labelled in Persian as John or Jane Doe, suggesting their identity was unknown when the photo was taken. Only 28 of the victims had labels with clearly visible names in the photos.

Labels on more than 100 victims, who had their date of death recorded, showed that date as 9 January, one of the deadliest nights for protesters in Tehran so far.

The city’s streets were set on fire during clashes with security forces, with protesters chanting slogans against the supreme leader and the Islamic Republic. It followed a call for nationwide protests from Reza Pahlavi, the exiled son of the late shah.

The leaked photos provide a small snapshot of the thousands believed to have been killed at the hands of the Iranian state.

BBC Verify has been tracking the spread of protests across Iran since they erupted in late December, but the near total internet blackout imposed by the authorities has made it extremely difficult to document the scale of the government’s violence against those who oppose it.

Iran’s Supreme Leader Ayatollah Ali Khamenei has publicly acknowledged several thousand people have been killed but blamed the US, Israel and those he described as “seditionists”.

Despite the blackout entering its third week, a small number of people have managed to get some information out.

Hundreds of close-up images of victims taken from inside the Kahrizak Forensic Medical Centre were leaked to BBC Verify.

We analysed 392 photos of victims and were able to identify 326 people – some had multiple pictures taken of them from different angles. Sources claimed the true number of dead at the mortuary ran into the thousands.

One source, who we are not naming for their safety, told us they weren’t prepared for the level of devastation they encountered inside the mortuary complex, and said they saw victims ranging from as young as 12 or 13 to 60 and 70-year-olds. “It was just too much,” they said.

Amid the chaos inside the mortuary, family members and friends were huddled together around a screen, we were told. They were trying to identify their loved ones while hundreds of images of the dead flicked across the screen.

The slideshow lasted for hours, they said, adding that many of the victims’ injuries were so severe they could not be identified. One man’s face was so swollen his eyes were barely visible. Another man still had a breathing tube in his mouth, suggesting he died after receiving medical treatment.

Some victims were so badly injured that their families asked to see the pictures again and to zoom in on their faces to make sure it was really them, we were told. At other times people recognised their loved ones instantly and were seen collapsing to the floor, screaming.

Many photos showed unzipped body bags with papers laid close to their faces, identifying them by name, ID number or date of death. In some cases, we were told, the only identifier was a bank card laid on top of a body bag – the victims’ last remaining possession.

BBC Verify has separately corroborated videos from the same mortuary that demonstrate the violence perpetrated against protesters. One shows the body of what appears to be a child, while another shows a man with a clear gunshot wound in the middle of his head. Both videos are too distressing to show.

Some Iranians have been posting the names of victims killed by security forces when they manage to connect to the internet through Starlink or even using networks from neighbouring countries, though these opportunities are incredibly rare.

We checked the names of victims identified in the mortuary against social media posts reporting the names of the dead and found five matches, but are not revealing the names as we cannot contact the victims’ families.

BBC Verify has tracked the spread of anti-government protests across 71 towns and cities in Iran since they first erupted on 28 December through verified video, though the true number of areas where demonstrations have taken place is likely much higher.

The few images that people have managed to upload through Starlink show burnt-out cars left in the streets, while verified videos recorded rounds of gunshots fired around Tehran during protests.

The internet blackout has made it extremely difficult to document the full extent of the death toll from the protests. However, US-based Human Rights Activists News Agency (HRANA) has placed its current estimate at more than 4,000 deaths.