United Nations (United States) - (AFP) - The European Union prepared Wednesday new sanctions to impose on Iran for supplying military drones to Russia , on the eve of the UN Security Council meeting to discuss Russia's drone attacks in Ukraine.

The United States, France and Britain requested a closed session of the Security Council to discuss the issue of Tehran supplying Russia with arms, according to diplomats.

Russia has veto power in the council and is expected to overrule any decision it makes. But the United States and France have warned that Iran, by arming Russia, is violating Security Council resolutions.

Ukraine reported weeks ago that Russia had launched Iranian Shahed-136 drones, drones whose warheads explode in suicide landings, and Kiev moved to sever ties with Tehran.

However, Iran and Russia denied using the drones, and Tehran expressed its desire to hold talks with Ukraine. But the European Union announced on Wednesday its assertion that Iran is behind supplying the drones to Russia.

"We have collected our own evidence," said Nabila Masrali, spokeswoman for EU foreign policy chief Josep Borrell, and the bloc was preparing for a "clear, swift and firm response."

A list seen by AFP showed that the European Union had prepared to impose sanctions on three Iranian military officials, including General Mohammad Bagheri, chief of the general staff of the Iranian armed forces.

The sanctions, which are expected to be approved Thursday at a European summit in Brussels, will include Shahed Aviation Industries, a company linked to the Revolutionary Guards.

On Wednesday, the Ukrainian military reported that it had shot down more than 220 Iranian-made drones in about a month, although the drone bombing of Kiev on Monday resulted in five deaths.

The United States accuses Iran, by transferring war drones to Russia, of violating UN Security Council Resolution No. 2231 of 2015, which sponsored a nuclear agreement that is now on the brink of collapse.

And in 2020, the ban imposed by the resolution on Iranian conventional arms sales ended, despite previous attempts by the Donald Trump administration to extend it.

But the resolution still prohibits, until October 2023, any transfers except with the permission of the Security Council if they benefit ballistic missile capabilities.

US State Department spokesman Vedant Patel said on Wednesday that "Iran's supply of these specific types of drones to Russia is a violation of UN Security Council Resolution 2231, and it is a matter for the UN Security Council."

The alleged arms transfers come as Iran faces mounting pressure over its crackdown on the country's biggest protests in years, following the death of 22-year-old Mahsa Amini while in the custody of the "morality police".

The unrest has led to new Western sanctions on Iran and a rollback in efforts by US President Joe Biden to revive the 2015 nuclear deal that Donald Trump withdrew from.

Western officials have highlighted the Iranian drones as evidence that Russia, historically one of the world's largest arms exporters, is depleting its arsenal from battlefield losses.

The United States revealed intelligence information saying that Iranian drones had malfunctions in many cases, and that Russia had turned to North Korea to obtain planes after China rejected invitations to send weapons.

Estonian Defense Minister Hanno Pevkur said during a visit to Washington that Russia relied on drones due to the lack of supplies and Ukraine's success in protecting its airspace.

Pevkor told reporters that the Russians "realize that in the air they have no control now, because there is air defense from the Ukrainian side. They have lost a lot of planes."