WATCH: State Department says U.S. will back sanctions against Iran over drone sales

The Biden administration is backing the European Union as it gathers evidence that Iran is supplying drones to Russia for use its war in Ukraine. The EU is drawing up a list of sanctions in retaliation, officials and diplomats said Wednesday.

Watch the briefing in the player above.

Russia is believed to have sent waves of Iranian-made Shahed drones over Ukraine to strike at power plants and other key infrastructure. EU foreign ministers discussed the use of drones Monday, as the 27-nation bloc gathered evidence about Iran’s alleged sale to Russia.

In Washington, State Department Deputy Spokesman Vedant Patel told reporters that the U.S. will join the British and French in raising this issue at a closed meeting of the Security Council, where members will hear from an expert briefer on the transfer of the drones from Iran to Russia.

“We would welcome the EU sanctioning Iran for supplying weapons to Russia,” Patel said.

“Also I would again note and reiterate that the United States itself continues to have tools at its disposal that are practical, that are aggressive, that are useful in holding Iran accountable,” he said.

READ MORE: Putin orders martial law in annexed Ukrainian regions; launches mass evacuations

An EU official and two EU diplomats said that the sanctions could be finalized as soon as Thursday, just as EU leaders are meeting in Brussels. The measures would involve an asset freeze on one “entity” – often a government agency, company or other organization – as well as asset freezes and travel bans several individuals with links to the drone sector.

The State Department is also strongly criticizing Russian President Vladimir Putin after he ordered martial law on Wednesday for four illegally annexed Ukrainian regions.

“It should be no surprise to anybody that Russia is resorting to desperate tactics to try and enforce control in these areas,” Patel said. “The truth is, is that Russia is not wanted in these regions and the people of Ukraine are rejecting Russia’s illegal invasion and seizure by force of what is Ukrainian territory,” he said.

Finally, Patel also criticized Iran for its treatment of women as Iranian climber Elnaz Rekabi returned to Tehran early Wednesday.Rekabi competed in South Korea without wearing a headscarf, an act widely seen as support for anti-government demonstrators amid weeks of protests over the Islamic Republic’s mandatory hijab.

The future Rekabi faces after returning home remains unclear. Supporters and Farsi-language media outside of Iran have worried about Rekabi’s safety after her return, especially as activists say the demonstrations have seen security forces arrest thousands so far.