Donald Trump repeatedly pressured Ukraine’s new leader to investigate the son of his potential rival in the 2020 presidential elections, according to US media.

Mr Trump was said to have badgered Volodymyr Zelensky to press ahead with the probe into Joe Biden’s son, even suggesting he work with his personal lawyer, Rudy Giuliani.

The Wall Street Journal said Mr Trump made the request to his Ukrainian counterpart eight times during the phone call in July. The Washington Post also said Mr Trump made the request during the call, which took place one day after former special counsel Robert Mueller testified before Congress about Russian interference in US elections.

“He told him that he should work with [Mr. Giuliani] on Biden, and that people in Washington wanted to know” if his lawyer’s assertions that Mr Biden acted improperly as vice president were true, the Journal reported.

The revelations will add to the controversy Mr Trump has found himself in over a complaint submitted by an intelligence whistleblower that involves a conversation Mr Trump had with a foreign leader.

Ukraine Elections 2019 in pictures Show all 26 1 /26 Ukraine Elections 2019 in pictures Ukraine Elections 2019 in pictures Volodymyr Zelenskiy, centre right, and his wife Olena Zelenska, greet supporters after exit polling gave the comedian a commanding lead AP Ukraine Elections 2019 in pictures Outgoing Ukrainian President Petro Poroshenko raises his hand with his wife Maryna at his party headquarters in Kiev AFP/Getty Images Ukraine Elections 2019 in pictures Ukrainian presidential candidate Volodymyr Zelenskiy reacts following the announcement of the first exit poll REUTERS Ukraine Elections 2019 in pictures Comedian and leading Ukrainian presidential candidate Volodymyr Zelenskiy plays ping pong with a journalist at his election night gathering in Kiev, Ukraine. If no candidate receives more than 50% of the vote, the top two vote-getters will face off in a second-round election on April 21 Getty Ukraine Elections 2019 in pictures Election officials count ballots at a polling station in Kiev during the first round of Ukraine's presidential election, AFP/Getty Ukraine Elections 2019 in pictures People walk in front of St. Sophia Cathedral in Kiev during Ukraine's presidential election AFP/Getty Ukraine Elections 2019 in pictures Ukrainian servicemen sit in a truck to head to a polling station, near the front line with pro-Russian separatists, near Butivka, Donetsk region AFP/Getty Ukraine Elections 2019 in pictures Ukrainian citizens living in Kyrgyzstan vote in Ukraine's presidential election at a polling station in the Ukrainian embassy in Bishke AFP/Getty Ukraine Elections 2019 in pictures Ukrainian citizens living in Kyrgyzstan vote in Ukraine's presidential election at a polling station in the Ukrainian embassy in Bishkek AFP/Getty Ukraine Elections 2019 in pictures Ukrainian citizens living in Kyrgyzstan vote in Ukraine's presidential election at a polling station in the Ukrainian embassy in Bishkek AFP/Getty Ukraine Elections 2019 in pictures Ukrainian citizens living in Kyrgyzstan vote in Ukraine's presidential election at a polling station in the Ukrainian embassy in Bishkek AFP/Getty Ukraine Elections 2019 in pictures A young girl casts the ballot of a man at a polling station in Kiev on the first round of Ukraine's presidential election, on. Exit polls are expected when voting stations close at 8 pm local time (1700 GMT). First preliminary results are expected several hours after. Barring a shock result in which one candidate crosses the 50 percent threshold in the first round, a run-off will be held on April 2 AFP/Getty Ukraine Elections 2019 in pictures Ukrainian comic actor, showman and presidential candidate Volodymyr Zelensky waves in front of voting booths at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Former Ukrainian Prime Minister and presidential candidate Yulia Tymoshenko speaks with the media after casting her ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Former Ukrainian Prime Minister and presidential candidate Yulia Tymoshenko speaks with the media after casting her ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Former Ukrainian Prime Minister and presidential candidate Yulia Tymoshenko speaks with the media after casting her ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Ukrainian comic actor, showman and presidential candidate Volodymyr Zelensky casts his ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Ukrainian comic actor, showman and presidential candidate Volodymyr Zelensky gestures in front of voting booths at a polling station during Ukraine's presidential election in Kiev AFP/Getty Images Ukraine Elections 2019 in pictures Ukrainian comic actor, showman and presidential candidate Volodymyr Zelensky walks with his ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Images Ukraine Elections 2019 in pictures A view of the building of the Ukrainian Central Election Commission in Kiev during Ukraine's presidential election. AFP/Getty Ukraine Elections 2019 in pictures Ukrainian President Petro Poroshenko (L) casts his ballot at a polling station in Kiev on the first round of Ukraine's presidential election, The 53-year-old president has positioned himself during the political campaign as the only person able to stand up to the Kremlin and has promised to return Crimea to Ukraine if he is re-elected. AFP/Getty Ukraine Elections 2019 in pictures A voter emerges from the voting booth after filling out her ballot for Ukraine's presidential election in Kiev, Ukraine. If no candidate receives more than 50% of the vote, the top two vote-getters will face off in a second-round election on April 21. Getty Ukraine Elections 2019 in pictures Ukrainian president Petro O. Poroshenko (C), running for re-election, receives his ballot in Ukraine's presidential election on in Kiev, Ukraine. If no candidate receives more than 50% of the vote, the top two vote-getters will face off in a second-round election on April 21 Getty Ukraine Elections 2019 in pictures A woman holds her ballot as she leaves a voting booth at a polling station in Kiev on the first round of Ukraine's presidential election. - Exit polls are expected when voting stations close at 8 pm local time (1700 GMT). First preliminary results are expected several hours after. Barring a shock result in which one candidate crosses the 50 percent threshold in the first round, a run-off will be held on April 21 AFP/Getty Ukraine Elections 2019 in pictures A young girl casts the ballot of a man at a polling station in Kiev on the first round of Ukraine's presidential election. Exit polls are expected when voting stations close at 8 pm local time (1700 GMT). First preliminary results are expected several hours after. Barring a shock result in which one candidate crosses the 50 percent threshold in the first round, a run-off will be held on April 21 AFP/Getty Ukraine Elections 2019 in pictures Ukrainian servicemen queue to cast their ballots at a polling station near the front line line with pro-Russian separatists near Avdiivka, Donetsk region, during the first round of Ukraine's presidential election AFP/Getty

Earlier this month, Democrats on Capitol Hill announced they were launching investigations into efforts by Mr Trump to ask Ukraine to interfere in 2020. The Democratic chairs of the house intelligence, oversight and foreign affairs committees wrote to the White House and state department seeking records related to what they described as efforts to “manipulate the Ukrainian justice system”.

The move came after reports that Mr Giuliani, the former New York mayor who has been advising Mr Trump on legal matters, has been pressuring Mr Zelensky to open proceedings into claims made by Republicans that Mr Biden acted unfairly to help his son, Hunter, in business dealings.

Mr Giuliani had been liaising with prosecutors in Kiev appointed by Mr Zelensky’s predecessors, to look into the company Hunter Biden worked for, and the oligarch who owned it.

On Thursday night Mr Giuliani insisted to CNN that he didn’t ask Ukrainian officials to investigate Mr Biden, but 30 seconds later said “of course” he did.

On Friday, before the revelations in Journal, Mr Trump claimed the whistleblower was “partisan”, while also insisting he had done nothing wrong.

Speaking to reporters in the Oval Office on Friday morning, Mr Trump said: “I can say it was a totally appropriate conversation.”

He added: “It was actually a beautiful conversation.”

The complaint against the president emerged this week but is still shrouded in mystery. Apparently made by a US intelligence officer who was listening in to a call between Mr Trump and a world leader, it was classed as “serious” and “urgent” by the intelligence watchdog.

However, the acting director of national intelligence has so far refused demands from congress to reveal the exact nature of the complaint.

The Trump administration has denied links between a $250m (£200m) aid payment to Ukraine and the provision of negative information about Mr Biden and his son Hunter’s business dealings in the east European country.

Mr Trump insisted the person who made the complaint against him was “partisan” before admitting he did not know their identity.

He said: “We don’t know the identity of the whistleblower, we just know that it was a partisan person, meaning they come from a different party,” adding that he “fights so hard for this country”.

When asked again if he knew anything about the whistleblower, the president, visibly annoyed, fired back: “You’re supposed to be the media, figure it out.” And in response to a question over whether the complaint involved Ukraine, he said: “I really don’t know.”

He said he was under no obligation to explain what he discussed with Mr Zelensky in one of several phone conversations with world leaders made in the days before the complaint was filed, saying: “It doesn’t matter what I discussed, but I will say this: somebody ought to look into Joe Biden’s statement, because it was disgraceful, where he talked about billions of dollars that he’s not giving to a certain country unless a certain prosecutor is taken off the case.

“So, somebody ought to look into that. And you wouldn’t, because he’s a Democrat. And the ‘fake news’ doesn’t look into things like that. It’s a disgrace.”

Mr Trump will meet Mr Zelensky at the United Nations general assembly in New York next week where, a US administration official told reporters, he will congratulate him on his anti-corruption efforts.

Adam Schiff, the Democratic chair of the House intelligence committee, has threatened to sue the administration if intelligence officials do not share the complaint. He said it was unprecedented for the acting director of national intelligence, Joseph Maguire, to refuse to share the briefing with congress.

“We cannot get an answer to the question about whether the White House is also involved in preventing this information from coming to congress,” Mr Schiff said. “We’re determined to do everything we can to determine what this urgent concern is to make sure that the national security is protected.”

Support free-thinking journalism and attend Independent events

Democratic congressman Jim Himes, who serves on the intelligence committee, told CNN he would not be surprised if Mr Trump was indeed having an “inappropriate” conversation with a foreign leader, but was concerned by the news that the complaint involved a promise. “What would make it corrupt or illegal,” he said, is that promise.