UNITED NATIONS, United States (AFP) — Russia has warned the United Nations not to probe alleged strikes by Iranian-made drones in Ukraine, joining Tehran in denying the weapons' origin as the European Union prepared new sanctions on Tehran.

The United States, France and Britain called a closed-door Security Council meeting on the alleged sale of drones to Russia, which they described as a violation of UN arms restrictions on Iran.

The European Union and United States both said they had evidence that Iran supplied the Shahed-136s, low-cost drones that explode on landing and are blamed for five deaths Monday in the capital Kyiv as well as for the destruction of civilian infrastructure.

Ukraine, which has moved to sever diplomatic relations with Tehran, says its military has shot down more than 220 Iranian drones in little more than a month and pictures have surfaced that appear to show an Iranian link.

But Russian diplomat Dmitry Polyanskiy on Wednesday denounced the "baseless accusations and conspiracy theories," citing as evidence that the Russian word for geraniums was written on the drones, formally known as unmanned aerial vehicles.

"The UAVs used by the Russian army in Ukraine are manufactured in Russia," Polyanskiy told reporters outside the Security Council.

"I would recommend that you do not underestimate the technological capabilities of the Russian drone industry."

But he warned against any UN probe on the ground in Ukraine as part of enforcement of the existing sanctions on Iran.

"The team doesn't have this mandate to conduct investigations; it is not part of the sanctions committee. So this would be absolutely unprofessional and political," he said.

If the UN Secretariat or Secretary-General Antonio Guterres still go ahead, "we will have to reassess our collaboration with them, which is hardly in anyone's interest," Polyanskiy said.

Iran's UN envoy, Amir Saeid Iravani, also rejected the "unfounded and unsubstantiated claims" on the drone transfers and said that Tehran, which has abstained in votes on the Ukraine war, wanted a "peaceful resolution" of the war.

The alleged arms transfers come as Iran is facing growing pressure over its crackdown on the biggest protests in years, which were sparked by the death of Mahsa Amini, a 22-year-old detained by the clerical state's notorious "morality police."