Iran is the first to admit that it has provided drones to Russia.
Iranian Foreign Minister Hossein Amir Abdulrahian told state media on the 5th that "we provided Russia with a limited number of drones before the Ukrainian war centers".
Ukraine and its Western allies have accused Russia of using Iranian drones to strike Ukraine in recent weeks.
Iranian authorities have denied the allegations, but eventually changed their position.
In a phone conversation with Ukraine's foreign minister last week, Amir Abdulrahian said the Ukrainian side would provide evidence that Russia used Iranian drones if it was available.
He also dismissed allegations that Iran had also provided missiles to Russia as "completely false."
"The consequences of Iran's collusion with Russia will far outweigh the gains from Russian aid," a spokesperson for Ukraine's foreign ministry said in a Facebook post.
Ukrainian authorities claim about 400 Iranian-made drones have already been used to attack Ukrainian civilians, and that Russian authorities have ordered about 2,000 from Iran.
The UK and EU have imposed sanctions on three Iranian generals and an arms company for providing drones to Russia.