The U.S. Treasury Department on Thursday placed sanctions on a member of Ukraine’s parliament for running an “influence campaign” against former vice president Joe Biden, dubbing the lawmaker “an active Russian agent for over a decade” who has maintained “close connections with Russian intelligence services.”

The sanctions against Andriy Derkach — who in an attempt to tarnish the Democratic nominee for president released pilfered and edited phone conversations that Biden had years ago with Ukraine’s leadership — come less than two months before the 2020 presidential election and mark the most aggressive public action the U.S. government has taken to date to stanch foreign interference ahead of the vote.

President Trump’s personal attorney Rudolph W. Giuliani has met at least three times with Derkach since late last year and publicized the Ukrainian lawmaker’s claims on his podcast and elsewhere, elevating what the Treasury Department has now characterized as a foreign interference campaign by an active Russian agent aimed at influencing the 2020 election. Giuliani met Derkach in Kyiv late last year, just as the House prepared to impeach Trump over a pressure campaign orchestrated by Giuliani to induce the Ukrainian government into announcing probes of Biden. Derkach later visited Giuliani in New York, months before he began releasing the tapes of Biden at news conferences in Kyiv.

Derkach “and other Russian agents employ manipulation and deceit to attempt to influence elections in the United States and elsewhere around the world,” Treasury Secretary Steven Mnuchin said in a statement. “The United States will continue to use all the tools at its disposal to counter these Russian disinformation campaigns and uphold the integrity of our election system.”

The Treasury Department said Derkach had “directly or indirectly engaged in, sponsored, concealed or otherwise been complicit in foreign interference in an attempt to undermine the upcoming 2020 U.S. presidential election.”

“Today’s designation of Derkach is focused on exposing Russian malign influence campaigns and protecting our upcoming elections from foreign interference,” the department said in a statement. “This action is a clear signal to Moscow and its proxies that this activity will not be tolerated.”

In addition to Derkach, the Treasury Department imposed sanctions on three individuals from the Internet Research Agency, the St. Petersburg-based troll factory that created fake accounts on social media during the 2016 campaign in attempt to influence the election. The department said the three individuals supported the IRA’s cryptocurrency accounts, which were used to fund such operations. One of them was also charged with a fraud conspiracy in the Eastern District of Virginia.

The sanctions come a day after a senior official at the Department of Homeland Security alleged in a whistleblower complaint that he was told to stop providing intelligence reports on the threat of Russian interference in the 2020 election in part because it “made the President look bad.”

Derkach, a former member of Ukraine’s Russia-leaning Party of Regions, was educated at the Higher School of the KGB in Moscow before entering business and politics in independent Ukraine after the Soviet Union’s collapse. His father was a longtime KGB officer who later ran independent Ukraine’s intelligence service in the late 1990s and early 2000s before losing his position amid a scandal over Ukrainian authorities’ involvement in the kidnapping and murder of a prominent journalist.

Nikolai Lakhonin, a spokesman for the Russian Embassy in Washington, didn’t comment on whether Derkach is an active Russian agent and referred questions about him to the Ukrainian Embassy. Lakhonin said that by imposing sanctions on Derkach, the United States was “trying to keep their favorite topic afloat.”

“In our opinion, these speculations have run their course and they are doing this on purpose in the context of the upcoming U.S. elections in November,” Lakhonin said in an email.

The Russian government has denied interfering in U.S. elections, despite extensive evidence of the activity presented in a 448-page report by former special counsel Robert S. Mueller III and a federal indictment that charged 12 named Russian intelligence officers with hacking and releasing emails from Hillary Clinton’s campaign manager and the Democratic National Committee in 2016.

In a statement to The Washington Post earlier this year, Derkach praised Giuliani for cooperating with his activities and denied working for or with any foreign intelligence agencies, saying such accusations were attempts to stop his work combating international corruption.

“There is not a single confirmed or reliable fact of my illegal activity or wrongful connections,” Derkach said in the statement. He said many high-ranking officials in countries that were once part of the Warsaw Pact studied at Moscow’s premier intelligence academy.

The Treasury Department said that all property interests Derkach holds subject to U.S. jurisdiction would be frozen, and that U.S. persons would be prohibited from engaging in any transactions with him. The sanctions also block entities that are 50 percent or more owned by Derkach from doing business in the United States.

Derkach didn’t respond Thursday to a request for comment on the sanctions. Andrew Bates, a spokesman for the Biden campaign, declined to comment.

Since last year, Derkach has been running a full-fledged campaign against Biden and former Ukrainian president Petro Poro­shenko from Kyiv, complete with an English-language website and YouTube channel and a conspiratorial flowchart featuring the former vice president and financier George Soros at the center.

The Ukrainian lawmaker called his campaign “Demo­Corruption,” making an array of spurious allegations — including some that Giuliani helped publicize in the United States — against Biden and U.S. officials who worked with him. In May, he began holding news conferences at which he revealed edited snippets of recordings from telephone conversations Biden had with Poroshenko while leading diplomacy toward Ukraine.

According to the Treasury Department, Derkach was waging an influence campaign that cultivated false and unsubstantiated narratives concerning U.S. officials in the 2020 vote and sought to spur corruption investigations in both Ukraine and the United States “designed to culminate prior to election day.” The Ukrainian lawmaker’s unsubstantiated narratives, the Treasury Department said, were pushed in Western media through coverage of his news conferences and interviews and statements he gave.

“Derkach almost certainly ­targeted the U.S. voting populace, prominent U.S. persons, and members of the U.S. government, based on his reliance on U.S. platforms, English-language documents and videos, and pro-Russian lobbyists in the United States used to propagate his claims,” the department said.

Derkach’s allegations were seized upon by One America News, a favorite network of the president that has featured pro-Trump conspiracy theories. One America News conducted interviews with Derkach and publicized his allegations against Biden, helping inject the narrative the Ukrainian lawmaker was seeking to promote into the American political ecosystem ahead of the election.

A spokeswoman for One America News did not respond to a request for comment.

The sanctions have punctuated a political dispute on Capitol Hill, where Democrats have warned that Senate Republicans risk legitimizing information from figures like Derkach as part of their probe into the Biden family and Ukraine.

“This is, of course, the same Kremlin agent who has been meeting and communicating with the President’s personal lawyer and peddling this false information to Congress,” House Intelligence Committee Chairman Adam B. Schiff (D-Calif.) said in a statement Thursday.

Derkach told The Post and other news outlets that he had also sent materials to Congress in an attempt to spark investigations into his claims there.

Sen. Ron Johnson (R-Wis.) and Sen. Charles E. Grassley (R-
Iowa), who are leading a Senate probe into Biden and Ukraine that the Democrats have decried as an election-year smear, have said they didn’t receive any information from Derkach in their probe, which is due to wrap up this month.

“Foreign election meddling in all of its forms from any corner of the globe cannot be tolerated. We commend the Trump administration for holding accountable perpetrators of foreign interference,” Grassley and Johnson wrote in a statement Thursday.

In a message to The Post sent late Thursday, Giuliani said neither he nor Trump knew anything about Derkach during the events of summer 2019 that formed the basis of the impeachment probe.

Giuliani said he met Derkach for the first time when the Ukrainian lawmaker came to the One America News studio in Washington in November 2019, suggesting he had met the Ukrainian lawmaker at least three times.

Giuliani also sought to distance himself from Derkach, saying most of the information the Ukrainian lawmaker provided he already had. “Haven’t heard from him in a long time so I don’t know how he is attempting to affect the election, if he is,” Giuliani said.

In an interview with The Post earlier this year, Giuliani said that he knew Derkach “quite well” and that the Ukrainian lawmaker “has been very helpful to me.”

Asked if Derkach, had provided him with materials, Giuliani said, “Oh, my God, yeah.”

Giuliani, who has been trying to spark Justice Department investigations into Biden, spoke extensively about the documents he received from Derkach. He said Derkach had reviewed and shared prosecutor files from Ukraine.

Giuliani denied he was being used as pawn in a Russian influence campaign, saying Derkach didn’t seem pro-Russian and appeared to be “totally dedicated to a free Ukraine.”

The former New York mayor said it would disturb him if Derkach were working for the Russians.

“Sure, it’d bother me. It would,” Giuliani said. “But I don’t depend on his credibility. I depend on the credibility of his documents.”

In his statement, Schiff took aim at Giuliani without mentioning him by name.

“This announcement should serve as a reminder to those in the United States that have elevated Derkach’s disinformation and engaged with him and other foreign actors spreading similar false narratives, that their work only advances Vladimir Putin’s interests and efforts,” Schiff said. “Americans alone should decide American elections.”

David L. Stern in Kyiv contributed to this report.