Derkach, who met with President Donald Trump's lawyer Rudy Giuliani in 2019, "has been an active Russian agent for over a decade" and is complicit in attempts to influence the upcoming presidential election, the Treasury said in a statement.

In May Derkach released edited recordings from 2016 of phone calls between then vice president Biden and Ukraine president Petro Poroshenko in which they discuss US policy toward Ukraine and Washington's desire for the removal of corrupt officials.

Derkach has repeatedly made allegations that Biden and Biden's son Hunter were involved in corruption and Ukraine, and alleged the tapes were further evidence of this, according to news reports.

Although the tapes provided no evidence of any wrongdoing, US conservatives seized on them as proof of what they allege is the Democratic candidate's cover-up of his son's former business ties in Ukraine.

The tapes were released six months after Giuliani traveled to Ukraine and met Derkach in December 2019 while searching for evidence to undermine Biden and bolster Trump's defense in his impeachment trial -- which focused on Trump's own dealings with Ukraine.

The Treasury also placed three Russians on its sanctions blacklist for their ties to the St. Petersburg social media troll factory the Internet Research Agency, which has been involved in election meddling in the United States and other countries since at least 2016.

The three -- Artem Lifshits, Anton Andreyev and Darya Aslanova -- IRA employees who work with its cryptocurrency accounts, the Treasury said.

"The IRA uses cryptocurrency to fund activities in furtherance of their ongoing malign influence operations around the world," it added.

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