Ukraine said on Friday that it will cut diplomatic ties with Iran in response to Tehran’s plan to equip Russian military with drones, a move President Volodymyr Zelenskiy described as “operation with evil.”

According to Zelenskiy, eight Iranian-made unmanned aerial vehicles have been shot down thus far in the fight.

Ukraine and the US have accused Iran of sending drones to Russia, which Tehran has denied.

“Today the Russian army used Iranian drones for its strikes. … The world will know about every instance of collaboration with evil, and it will have corresponding consequences,” Zelenskiy said in a late night video address.

Military authorities in southern Ukraine said in a statement they had shot down four Shahed-136 “kamikaze” unmanned aerial vehicles over the sea near the port of Odesa on Friday.

The air force said separately that for the first time it had brought down a Mohajer-6, a larger Iranian drone, the Ukrainska Pravda newspaper reported.

The Ukrainian foreign ministry earlier said the supply of drones had dealt a serious blow to bilateral relations.

“In response to such an unfriendly act, the Ukrainian side has decided to deprive the ambassador of Iran of his accreditation and also to significantly reduce the number of diplomatic staff of the Iranian embassy in Kyiv,” it said in a statement on its website.

Because the permanent envoy, Manouchehr Moradi, is presently not in Ukraine, the message was delivered to the acting ambassador.

According to military experts, the drones would be helpful for both reconnaissance and as loitering weapons that could bide their time before identifying and engaging suitable targets.

A senior US administration official stated in August that Russia had experienced “many malfunctions” with Iranian-made drones obtained from Tehran.