A war of words has broken out over a mass grave found near an army base in Mali, recently used by French forces.
France has accused Russian mercenaries working in Mali of a smear campaign, involving dumping bodies there in order to blame the French.
But that's been rejected by the Russian government, and the Malian authorities have voiced their unhappiness at the French allegations.
France, which has had thousands of troops in Mali since 2013, announced in February it was pulling out of the country, amid controversy over its role fighting jihadist groups there.
France and other European countries have grown increasingly concerned over the presence of mercenaries from the Russian private military company, Wagner, in some African countries. The Russian government denies any links to Wagner.
What does France say happened?
French forces handed over a military base at Gossi to the Malian authorities on 19 April, and Malian soldiers moved in that day - one fact on which all parties involved in this agree.
On the afternoon of 20 April, the French army says its aerial reconnaissance showed a number of other soldiers, whom they describe as "Caucasians [Europeans] suspected of belonging to the Wagner group", arriving at this base unloading equipment with local Malian troops.
However, the soldiers' uniforms do not appear distinct because of the low quality of the footage, and it's difficult to say with certainty who they are.
The French authorities have told the BBC they can't share the original (higher quality) footage for security reasons.
That evening, the French say a Twitter account - @DiaDiarra6 - posted a claim that corpses had been found at Gossi, left by the departing French forces, but with no footage to illustrate this.
The Twitter handle describes the account holder as "a retired soldier, Malian patriot and a political analyst".
The French army says after noticing this tweet, it sent up a drone to check out what was happening.
The following day, at 07:50 local time (08:50 BST), the French army says it captured aerial images roughly 3km (1.8 miles) from the base of a group of "Caucasian individuals" near about 10 bodies, which were having sand thrown over them by some people, while others stood nearby filming.
About two hours later, @DiaDiarra6 - which the French described as "most likely a fake account created by Wagner" - posted again, this time with content too graphic to publish.
It shows a close-up shot of what appears to be a number of dead bodies lying covered in places by sand or dirt.
"This is what the French left behind when they left the base at Gossi. These are excerpts from a video that was taken after they left," the caption said.
Later that day, the Twitter account published a 20-second long video showing the same bodies. The account has since been deactivated.
What does Mali say happened?
Mali says that after taking control of the base on 19 April, a reinforcement force was sent there on 20 April, but it came under fire that night, from unknown attackers.
A reconnaissance patrol was sent out in the morning to check the area and at about 06:30 local time that day, it discovered the mass grave.
Army spokesman Col Souleymane Dembele said the advanced state of decomposition of the bodies meant they had been dead for some days, and this, he claimed, would rule out the involvement of Malian forces.
"The state of advanced putrefaction of the bodies indicates that this mass grave existed well before the [French] handover [to Mali]," he said.
During a press conference on 25 April, Col Dembele added that "some local residents had already reported this discovery [of the grave] when Malian authorities went to the site".
It's not clear whom the Mali authorities think are responsible for these deaths. But they have accused the French of espionage for flying a drone near the base. France said it has done nothing wrong because it is allowed to carry out surveillance in this area.
What has Russia said about this?
Russia's foreign ministry has issued a statement about the incident, voicing its support for Mali and accusing France of shifting the blame for the deaths on to others.
The statement mentions claims on social networks about the bodies found at Gossi, "which was until recently...where the French operation was located".
It then says local media have linked the discovery to reports about a group of local herders detained by French soldiers near Gossi. "Their fate is still unknown," it claims.
French media reports say that its forces had made some arrests in this area on 17 April. France says these people have now been released, which would rule them out being the victims found at Gossi.
It's worth saying that the Russian statement does not address the French accusation about suspected Wagner mercenaries. We have asked the Russian government for a response.
What conclusions can we draw?
Some things stand out about the Twitter account the French accuse of spreading disinformation, which do fuel suspicions about it.
It was only created in January this year and had been posting in support of the Malian army and Russia, and against the French presence.
The owner had a profile picture which we have traced to a VKontakte (a Russian social media platform) account of someone from Colombia.
The Twitter account then dropped this profile image and started to use one belonging to Mali's military leader, Assimi Goita, around the time it posted claims about the mass grave in Gossi.
We do not know why the first tweet accusing the French of responsibility for the deaths was sent out the evening before it appears the bodies were actually buried near the base.
Who were the victims in the grave?
As yet, we have no confirmation of the identity of the victims.
The French military says it believes they may have come from Hombori (south of Gossi), where the Malian army and Russian mercenaries carried out an operation on 19 April, during which the French claim a Russian fighter died.
The Malian army has acknowledged there was an incident here, saying one of its soldiers and 18 militants were killed.
It said the army arrested more than 600 suspects and later released most of them, with the remainder handed on to the police. One of those later died in custody, it says.
Meanwhile, the Mali government has launched an inquiry into the mass grave, but it has yet to determine who the victims were.
We have asked the army in Mali for a response.
BBC