The US says it agrees with Western allies that Iran’s supply of explosive drones to Russia violates UN sanctions.
Kyiv was struck by so-called “kamikaze” drones on Monday, unleashed by Russia but believed to be Iranian-made.
The US agrees with the French and British assessment that the drones violate UN Security Council Resolution 2231, the US State Department said.
That resolution, linked to Iran’s nuclear accord, bars Iranian transfers of certain military technologies.
Ukraine has identified the drones – or unmanned aerial vehicles (UAVs) – as Iranian Shahed-136 weapons. They are called kamikaze drones after the Japanese fighter pilots who flew suicide missions in World War Two.
“It is our belief that these UAVs that were transferred from Iran to Russia and used by Russia in Ukraine are among the weapons that would remain embargoed under 2231,” said Vedant Patel of the state department.
Iran, however, denies supplying them to Russia, but Mr Patel said the US “exposed publicly that Russia has received drones from Iran, that this was part of Russia’s plan to import hundreds of Iranian UAVs of various types”.
He added that there was “extensive proof” of Russia’s use of them in Ukraine.
Critical infrastructure was hit on Monday in Ukraine’s Kyiv, Dnipro and Sumy regions, with electricity cut in hundreds of towns and villages, the Kyiv government said.
At least eight people were killed – four in Kyiv and four in Sumy. The US said it would “hold [Russia] accountable for its war crimes.” BBC