Mali accused the French army of “spying” and “subversion” on Tuesday after it used a drone to film mercenaries burying bodies near a military base.

According to the junta, the drone “illegally” flew over the Gossi base on April 20, the day after French forces returned the site to Mali.

The French army released a video the next day that it claimed showed Russian mercenaries covering bodies with sand in order to falsely accuse departing troops of war crimes. Two soldiers were spotted filming the half-buried bodies.

Mali’s military had earlier announced an investigation into the discovery of a mass grave at the Gossi base.

The army claimed it discovered the grave the day after the images were published, and that the advanced stage of putrefaction of the bodies ruled out Malian soldiers’ involvement.