Warning: This story contains descriptions of torture and physical violence. Some readers may find it distressing.

A shopkeeper has told the BBC how Russian mercenaries fighting jihadists in Mali carried out the cold-blooded murder of two men in front of him and then threatened to chop off his fingers and kill him too.

This is one of several similar testimonies collected by the BBC showing the tactics used by the Russian fighters as they waged a brutal counter-insurgency operation against Islamist militants in the West African nation - methods widely condemned by human rights groups.

A military junta seized power in Mali in 2021, forcing French troops to leave after accusing them of failing to stem the insurgency. The junta pivoted towards Russia, enlisting the help of the Wagner mercenary group, which was at the time linked to the Kremlin.

Wagner has since pulled out of the country, and its operations have been taken over by Africa Corps, which falls under Russia's defence ministry.

Some of the Wagner mercenaries highlighted their atrocities on an invitation-only Telegram group until it was shut down in the middle of this year, said a report released by the European Council on Foreign Relations last month. They regularly shared photos and videos of murder, rape, torture, cannibalism and desecration of corpses against alleged insurgents and civilians, the report added.

In June, the Africa Report publication said it had infiltrated the Wagner-linked Telegram channel, finding 322 videos and 647 photographs of atrocities, including severed heads and gouged-out eyes, and posts laced with racism.

The shopkeeper we spoke to has fled Mali and is now living in a refugee camp across the border in Mauritania. We have named him Ahmed, and have changed the names of all the victims quoted in this article for their own safety.

He told the BBC his ordeal started when the Wagner combatants drove up to the big store that he ran in the central town of Nampala in August 2024.

Despite being regular customers, the Wagner fighters wanted to detain his boss, and accused him of colluding with the jihadists who have a strong presence in the region, Ahmed said. They took me to the vehicle and pushed me inside and tied my hands, he added.

A Wagner soldier took a knife and placed it on my finger, and asked me: 'Where is the shop owner?' I told him he is in [the capital] Bamako, but he replied: 'Wrong answer'.

Ahmed said the Wagner men, who spoke through an interpreter, then took him to a well-fortified Malian military base, and put him in a hangar.

I and three Wagner guys were in the hangar. They filled a tank with water and asked me to take off my clothes. I did. They dipped my head in the water until I was almost suffocating and I fell. Then they put their feet on my chest and I started to breathe [heavily].

Then they dipped my head in the water again and asked me for the second time about the shop owner and I told them he is in Bamako, Ahmed said, adding that the torture was repeated for a third time, and he gave the same answer.

After this ordeal, Ahmed said he was thrown into a small toilet block, where there were other local people he knew - including Hussein, who had been so badly beaten that he could not recognise him at first.

About 40 minutes later, they brought Umar [another acquaintance]. He too was in a terrible situation. They had tortured him. We slept in that toilet and the next morning they brought a piece of bread and a small cup of coffee, Ahmed said.

He said he was taken back to the hangar, where the Russian fighters wrapped a bandage around his face and head. He couldn't see, speak, or hear. They put a knife on his throat and threatened to behead him if he didn't give them the information they sought.

Ahmed detailed horrific scenes, including witnessing the executions of two other prisoners who were beheaded in his presence. His close brushes with death left him traumatized, leading him eventually to seek safety in Mauritania with his family.

The ongoing conflict in Mali has displaced nearly 50,000 people to refugee camps as security deteriorates amid violence from Russian-backed mercenaries and local insurgent groups.

Ahmed’s story is just one among many in the continuing plight of the people of Mali, highlighting the urgent need for international attention and action regarding human rights violations associated with mercenary operations.