MILAN — The Ukrainian military has begun utilizing first-person-view drones with a thermite spray capability over forested areas where Russian troops and equipment are hiding, a tactic that experts say can be a legitimate weapon of war, but only under strict circumstances.
On Sept. 2, footage emerged online showing what appeared to be a Ukrainian low-cost first-person-view drone, or FPV, carrying an incendiary burning mixture that it sprayed along a dense line of trees where Russian troops were suspected.
It was later reported by Ukrainian media outlet Militarnyi that the Ukrainian Mountain Infantry had received thermite munitions – which include a powdered mix of aluminum and iron oxide capable of burning at temperatures exceeding 2,200 degrees Celsius – that were mounted on drones and dropped on Russian positions.
Experts believe that the use of such weapons is two-fold, acting as both a cheap way to expose enemy locations and to cause fear among the invading troops.
“The primary use of these thermite FPV drones is as a defoliant to remove the tree and foliage cover that Russian troops and vehicles are using for concealment in tree lines; and secondarily likely intended as a psychological weapon due to the nature of the effects thermite would produce in contact with skin,” Justin Bronk, senior research fellow at the London-based Royal United Services Institute, said.
In addition, the high-temperatures of the blend can damage or destroy caches of equipment and ammunition in a single sortie, Federico Borsari, resident fellow at the U.S. Center for European Policy Analysis, noted.
“They can be employed for specific purposes for which explosive effects are not ideal, and be useful to burn abandoned vehicles, for instance, saving explosive warheads for missions requiring kinetic effects,” he said.
The two experts said FPVs are suitable drone variants to deliver the burning mixture at slow speed because of their low cost and precise maneuverability.
As incendiary weapons have become more common in the war, analysts have been flagging concerns over harm to civilians. For example, in 2023, Russia reportedly used thermite bombs in eastern Ukraine over residential neighborhoods, according to a video on social media that was picked up by the Youtube channel of The Telegraph newspaper.
Dangers in using thermite include the possibility of causing out-of-control fires that risk burning down civilian infrastructure and non-military targets.
The use of thermite munitions is not banned per say, but neither is it straightforward, experts say.
“It would be legitimate and legal to use them as defoliants to remove cover, and this holds unless they would a) hit civilians or b) there was a significant risk the subsequent fire would endanger civilians – contrast this with Russian use of thermite last year in an indiscriminate manner,” Matthew Savill, director of military science at RUSI, wrote in an email to Defense News.
Under the Geneva Conventions, deliberately targeting civilian areas with incendiary weapons constitutes a war crime, yet Moscow has paid little consideration to adhering to international norms during the course of the war.
Russian forces have used other fire-inducing weapons such as the 9M22S incendiary cluster rocket, used for the 122mm caliber Grad rocket artillery system, Bronk said.
Savill notes that throughout the war, Ukraine has largely been able to contrast its adherence to international conflict laws against Russian behavior, an important appearance he presumes Kyiv will strive to maintain.
“I would expect that however they choose to use thermite, they would want to keep that distinction,” he said.
Elisabeth Gosselin-Malo is a Europe correspondent for Defense News. She covers a wide range of topics related to military procurement and international security, and specializes in reporting on the aviation sector. She is based in Milan, Italy.
