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Ukrainian President Volodymyr Zelensky called for an investigation Wednesday of leaked recordings purportedly depicting then-Vice President Joe Biden telling Zelensky's predecessor Petro Poroshenko that his country would receive U.S. aid once top prosecutor Viktor Shokin was replaced.

The presumptive Democratic presidential nominee already has acknowledged such an arrangement publicly. But the leaked audio revived criticism that Biden was engaged in a kind of quid-pro-quo, much like President Trump was accused -- during impeachment proceedings -- of linking U.S. aid to calls for Zelensky to probe Shokin's ouster.

The new audio indicates Poroshenko went along with Biden's plan but did not think Shokin was involved in wrongdoing.

Shokin purportedly has said under oath that he had launched a probe concerning Hunter Biden's role at Ukrainian energy firm Burisma Holdings when he was ousted. Hunter Biden held a lucrative post there, despite limited expertise, while his father handled Ukrainian policy as vice president. At the least, Ukrainian prosecutors had previously been investigating Burisma's founder. Biden's defenders have argued his intervention had nothing to do with Burisma and was focused on corruption concerns.

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Zelensky said at a news conference in Ukraine that the contents of the leaked conversations, however, “might be perceived, qualified as high treason,” according to The Washington Post. Ukrainian prosecutors have said they are looking into sweeping "international corruption." Zelensky has tried to maintain good relations with the Trump administration, even as his 2019 discussions were at the core of the U.S. president's impeachment.

Andriy Derkach, a member of Ukraine's parliament, released the recordings a day earlier.

“It’s going to be critical for him to work quickly to repair the damage that Shokin did,” the man identified as Biden says in one clip. “And I’m a man of my word. And now that the new prosecutor general is in place, we’re ready to move forward to signing that new $1 billion loan guarantee. And I don’t know how you want to go about that... I’ll leave it to you to how you want it done and where you want it done."

The Washington Post and other outlets have reported on the audio clips, noting that Derkach was "previously aligned with a pro-Russian faction and has past links to Russian intelligence." Derkach's father reportedly worked for the KGB -- and was allegedly terminated amid a scandal "over a Ukrainian journalist who was kidnapped and murdered."

Poroshenko reportedly blamed Russia for the leak, calling the audio "bogus" and seeking an investigation of the leak itself.

In the audio recordings, Biden purportedly says it was critical for Shokin's replacement to "work quickly to repair the damage Shokin did." Shokin has been accused of corruption, although Shokin -- as well as Trump attorney Rudy Giuliani -- have suggested the allegations are a smear campaign.

"I have an affidavit here that's been online for six months that nobody bothered to read from the gentleman who was fired, Viktor Shokin, the so-called corrupt prosecutor," Giuliani said last year. "The Biden people say that he wasn't investigating Hunter Biden at the time. He says under oath that he was." The Shokin affidavit purportedly said the U.S. had pressured him into resigning because he was unwilling to drop the case. In response, the Biden presidential campaign sought to bar Giuliani from television.

Biden has previously acknowledged on camera that in spring 2016, when he was vice president and spearheading Ukrainian policy, he successfully pressured Ukraine to fire Shokin. However, Biden claimed that he applied that pressure, with then-President Barack Obama's approval, because of concerns about corruption.

The vice president said he had threatened to withhold $1 billion in critical U.S. aid if Shokin was not fired. "Well, son of a b---h, he got fired," Biden joked at a panel two years after leaving office.

The new recordings, however, appear to show Poroshenko saying he had "no information" that Shokin had done "something wrong."

"Yesterday I met with General Prosecutor Shokin, and despite of the fact that we didn’t have any corruption charges, we don’t have any information about him doing something wrong, I specially asked him -- no, it was day [sic] before yesterday -- I specially asked him to resign in his position as a state person," Poroshenko apparently said on Feb. 18, 2016, according to Derkach's clip. "And one hour ago he bring [sic] me the written statement of his resignation. And this is my second step for keeping my promises.“

"I agree," Biden responds.

The leaked recordings, which Derkach claimed initially had been obtained by investigative journalists, prompted an outcry among conservatives.

"Yikes!!!! This is not a 'perfect conversation,'" wrote Donald Trump Jr., referring to the term President Trump has used to describe his infamous conversation with Zelensky, which led to his impeachment trial.

Fox News has not independently confirmed the authenticity of the recordings, which were evidently edited down to a series of clips whose full context is not clear.

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The communications also indicated that other Obama administration officials were aware of the Ukrainian arrangement. "I just wanted to try to urge you to see if there's a way to get by this problem of replacing the prosecutor general, you know, Shokin because per my perception, he's blocked the cleanup of the Prosecutor General's Office," then-Secretary of State John Kerry purportedly says at the beginning of one of the calls, on Dec. 3, 2015.

The released clips were relatively short and disjointed in nature, and the Biden campaign sought to downplay their significance.

“They heavily edited this, and it’s still a nothing burger that landed with a thud," Biden spokesperson Andrew Bates said, according to The Post.

Dec. 4, 2013: Vice President Joe Biden, left, waves as he walks out of Air Force Two with his granddaughter Finnegan Biden and son Hunter Biden at the airport in Beijing, China.

Dec. 4, 2013: Vice President Joe Biden, left, waves as he walks out of Air Force Two with his granddaughter Finnegan Biden and son Hunter Biden at the airport in Beijing, China. (AP)

The campaign did not offer additional on-the-record comment when asked by Fox News.

However, the Bidens' overseas dealings will likely remain an issue in the 2020 presidential race.

In the ABC News report last year, which also delved into the Bidens' China dealings, journalist Tom Llamas called it "strange" that Ukrainian natural gas company Burisma Holdings, which had been accused of corruption, had appointed Hunter Biden to its board of directors -- and agreed to pay Hunter Biden's company "more than a million dollars a year."

"He had served on other boards, but had no known experience in Ukraine or natural gas," Llamas noted.

During the House impeachment proceedings earlier this year, a career State Department employee testified that he had flagged Hunter Biden's apparent conflict of interest, given that his father was overseeing Ukrainian policy while Hunter sat on Burisma's board. But the official, George Kent, said he was told essentially not to bother the vice president's office.

In February, Senate Finance Committee Chairman Chuck Grassley, R-Iowa, and Senate Homeland Security and Governmental Affairs Committee Chairman Ron Johnson, R-Wis., announced in a letter they are seeking "records of Hunter Biden’s travel while he was under U.S. Secret Service protection as they continue to investigate potential conflicts of interest to boost his business ventures in Ukraine and China."

"We write to request information about whether Hunter Biden used government-sponsored travel to help conduct private business, to include his work for Rosemont Seneca and related entities in China and Ukraine," the senators wrote, referring to the company co-founded by the younger Biden.

READ THE LETTER TO THE SECRET SERVICE

Grassley and Johnson suggested the Secret Service might have information concerning Hunter Biden's dealings in those countries, especially concerning his position as one of nine directors at BHR -- a private-equity company controlled by Chinese government-backed stakeholders.

"In December of 2013, one month after Rosemont Seneca's joint venture with Bohai Capital to form BHR, Hunter Biden reportedly flew aboard Air Force Two with then-Vice President Biden to China," the senators wrote. "While in China, he helped arrange for Jonathan Li, CEO of Bohai Capital, to 'shake hands' with Vice President Biden."