The government in Kyiv announced on Friday that it was significantly reducing Iran's diplomatic representation in Ukraine.
The move followed the killing of a Ukrainian civilian in the port of Odessa in a Russian attack carried out on Friday using a drone which, Ukraine's army said, had been supplied by Iran.
"In response to such a hostile act, Ukraine has decided to de-accredit the Iranian ambassador to Ukraine and significantly reduce the number of diplomatic staff at the Iranian embassy in Kyiv," Ukraine's Foreign Ministry said in a statement.
The decision was communicated to the Iranian diplomatic mission in Ukraine on Friday.
"Supplying weapons to Russia to wage war in Ukraine is a hostile act that has serious consequences for Ukrainian-Iranian relations," Kyiv said.
According to the Ukrainian army, an Iranian Shahed-136 drone was shot down over the sea in Friday's attack in Odessa. Another Iranian drone was also shot down elsewhere in Ukraine.