Ukraine has been using the German-made Gepard anti-aircraft gun to shoot down Russia's Shahed-136 drones.
The Iranian-made Shahed loitering munitions have been implemented by Russia to strike Ukrainian cities and infrastructure.
Airpower and military technology expert Justin Bronk, from the London-based defence and security think tank RUSI, told Forces News that the Gepard "is very effective against them... because it has air-bursting" 35mm ammunition.
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Mr Bronk explained that the Shahed is "essentially a propellor-powered missile that can loiter for a period because it's just a propellor-powered thing with some wings".
"It's relatively dumb, it has GPS guidance. It will fly to a target point, and can then pick its angle of attack... so it'll circle until it gets to the right bearing that you've set, and then it can pop up and potentially dive."
The airpower and military technology expert added that "it's effective, it works, and it's cheap".
"You either need a lot of bullets fired quite accurately to hopefully hit a key component...or you need something like air-bursting ammunition.
"So this is one of the reasons why the German Gepard is very effective against them."
The US first revealed this summer that Russia was purchasing Iranian unmanned aerial vehicles to launch against Ukraine.
Iran recently acknowledged sending drones to Russia, for the first time – but says it was before the war in Ukraine.
Iranian Foreign Minister Hossein Amirabdollahian confirmed a "small number" of drones had been supplied to Russia.