Donald Trump has retweeted an audio recording that US intelligence officials have described as part of a Russian campaign to undermine Democratic presidential candidate Joe Biden.

The leaked conversation, purportedly between Mr Biden and former Ukrainian president Petro Poroshenko, dates from February 18 2016, and centres on the resignation of Ukraine’s chief prosecutor.

By amplifying the recording to his more than 85 million Twitter followers, Mr Trump underscored the ease with which pro-Moscow narratives can seep into American public discourse ahead of the November election despite being flagged by intelligence officials as the product of a concerted Russian effort.

Russia has also published disinformation under the guise of legitimate news stories, US officials say, reflecting a shift in tactics from 2016, when Moscow relied on a social media campaign to sow discord and also orchestrated the release of stolen Democratic emails.

The Biden campaign accused Mr Trump in a statement of having “habitually attacked the sovereignty of American elections”, including by “attempting to coerce his Ukrainian counterpart into spreading conclusively disproved lies”.

That is a reference to a July 2019 phone call in which the president encouraged his Ukraine counterpart, Volodymyr Zelenskiy, to investigate unsubstantiated corruption allegations against Mr Biden. The call was at the centre of the impeachment case against Mr Trump that ended with his acquittal by the Senate in February.

“Donald Trump is the most hostile president to American democracy in our history,” said Biden campaign spokesman Andrew Bates.

Andrii Derkach, a member of Ukraine’s parliament and a 1993 graduate of a Russian spy academy who has long aired corruption allegations against Mr Biden and his son, has this year released what he says are recordings of conversation between Mr Poroshenko and Mr Biden when the Democrat was vice president during the Obama administration.

That effort was flagged in a US intelligence assessment earlier this month warning of Russian interference in the election, and specifically efforts to denigrate Mr Biden.

“For example, pro-Russia Ukrainian parliamentarian Andriy Derkach is spreading claims about corruption — including through publicising leaked phone calls — to undermine former vice president Biden’s candidacy and the Democratic Party,” said the statement from William Evanina, the US government’s chief counter-intelligence official.

Joe Biden
Joe Biden (Carolyn Kaster/AP)

In the conversation retweeted by the US president, Mr Poroshenko can be heard telling Mr Biden he had accepted the resignation of prosecutor Victor Shokin “despite of the fact that we didn’t have any corruption charges, we don’t have any information about him doing something wrong”.

An anti-Biden narrative pushed by Mr Trump and his supporters alleges that the Democrat, as vice president, pressured Ukraine’s government to fire Mr Shokin because had investigated a Ukrainian energy company on whose board Mr Biden’s son Hunter sat. But Mr Biden’s position on the prosecutor, who was seen by critics as soft on corruption, was the position of the US government and was also supported by other Western governments and many in Ukraine.

The Twitter user who Mr Trump retweeted said in his post that the conversation revealed that “Shokin was not corrupt” and there was no information to suggest he had done anything wrong.

A White House summary of the conversation available online does show that Mr Biden and Mr Poroshenko spoke on February 18 2016, but Mr Poroshenko has generally rejected the tapes disclosed by Mr Derkach as a fabrication by pro-Russian forces in Ukraine.