The whistleblower who claimed Donald Trump repeatedly pressured the Ukraine president to investigate Joe Biden and his son Hunter for corruption during a phone call did not actually listen to the communication between the leaders, it has been reported.

A source told CNN that the official 'did not have direct knowledge of the communications' instead relying on 'learning information that was not obtained during the course of their work'.

It is those details that have reportedly played a role in a decision that the 'complaint did not fit the requirements under the intelligence whistleblower law', the official added.

The House Intelligence Committee had been demanding it be given the whistleblower's complaint in line with a finding by the inspector general for the intelligence community that the matter met the legal threshold for transmission to Congress.

Acting Director of National Security Joseph Maguire, however, decided against providing the complaint to the committee after he consulted with the Justice Department, and reportedly the White House.

Maguire and his top lawyer contended the complaint did not meet the legal guidelines for submission to the committee, prompting Democrats to accuse Maguire of breaking the law.

The whistleblower who claimed Donald Trump repeatedly pressured the Ukraine president to investigate Joe Biden and his son Hunter for corruption during phone call did not actually listen to the communication between the leaders, according to a source

When Joe Biden was VP, son Hunter served as director of Ukrainian gas firm. Then-VP Biden pressured Ukraine to fire prosecutor investigating firm's owner and the fired prosecutor's successor closed the investigation into Burisma Holdings

The president on Saturday tweeted a quote by Tom Fitton, who heads the conservative activist group Judicial Watch. Fitton said the Ukraine issue was being used to 'protect the Obama/Clinton gang.' He added that the scandal was being fueled by 'criminal classified leaks' and 'spying targeting Trump'

The president tweeted: 'They’re trying to turn what was a Biden scandal into a Trump scandal. @PeterSchweizer The problem is, “Trump” did nothing wrong!' Peter Schweizer is an author who has written a number of books about alleged corruption scandals by Democrats

Andrew Bakaj, the whistleblower's attorney, did not comment on the latest claims.

But a source close to the official said it 'seems like the beginning of a smear by those trying to discredit the whistleblower'.

Biden said Saturday: 'I have never spoken to my son about his overseas business dealings. Here’s what I know. Trump should be investigated.'

But in an interview with The New Yorker two months ago Hunter recalled Joe spoke with him about Burisma Holdings, the Ukrainian natural gas company, saying: 'Dad said "I hope you know what you are doing", and I said "I do".'

A visibly angry Biden said while campaigning in Iowa Saturday: 'This appears to be an overwhelming abuse of power. To get on the phone with a foreign leader who is looking for help from the United States and ask about me and imply things, this is outrageous.'

'Trump is using this because he knows I'll beat him like a drum and is using the abuse of power and every element of the presidency to try to do something to smear me,' Biden added.

Trump's July 25 telephone call with Ukrainian President Volodymyr Zelenskiy is at the center of an escalating battle over a whistleblower's complaint reportedly concerning the U.S. leader's dealings with Ukraine that the administration has refused to give Congress.

The Wall Street Journal and other news outlets on Friday said Trump repeatedly asked Zelenskiy to investigate unsubstantiated charges that Biden, while vice president, threatened to withhold U.S. aid unless a prosecutor who was looking into a gas company in which Biden's son was involved was fired.

Trump called his conversation with Ukrainian President Volodymyr Zelenskiy, pictured, 'perfectly fine and routine'

Trump, reports said, urged Zelenskiy, a comedian who had just won election, to speak with Trump's personal lawyer, Rudolph Giuliani.

Giuliani, the former New York City mayor, has promoted the allegations against Biden and his son, Hunter, and acknowledged that he pressed for a Ukrainian investigation.

Biden has admitted threatening to withhold aid unless the prosecutor was dismissed, a demand also made by the wider U.S. government, the European Union and other international institutions for his alleged failure to pursue major corruption cases.

The news reports about the Zelenskiy phone call have intensified demands by Democratic lawmakers for the House of Representatives to launch impeachment proceedings against Trump, and have elevated the controversy to a major campaign issue.

Trump denied doing anything improper. He wrote in a series of tweets on Saturday that his conversation with Zelenskiy was 'perfectly fine and routine.'

He accused the 'Fake News Media and their partner, the Democrat Party' of staying 'as far away as possible' from the Biden allegations.

Trump also tweeted a number of quotes from supporters of his who accuse the president's enemies in government of spying on him.

The president tweeted: 'They’re trying to turn what was a Biden scandal into a Trump scandal. @PeterSchweizer The problem is, “Trump” did nothing wrong!'

Peter Schweizer is an author who has written a number of books about alleged corruption scandals by Democrats.

Joe Biden, pictured Sunday working the grill at the Polk County Democrats' Steak Fry, has admitted threatening to withhold aid unless the prosecutor was dismissed, a demand also made by the wider U.S. government, the European Union and other international institutions for his alleged failure to pursue major corruption cases

In 2014, Viktor Shokin (left), Ukraine's top prosecutor, investigated the owner of Burisma, a Ukrainian gas company where Hunter Biden held a directorship. Joe Biden led international efforts to have Shokin fired. He was replaced by Yuriy Lutsenko (right), who dropped the investigation into Burisma's owner

The president on Saturday also tweeted a quote by Tom Fitton, who heads the conservative activist group Judicial Watch.

Fitton said the Ukraine issue was being used to 'protect the Obama/Clinton gang.'

He added that the scandal was being fueled by 'criminal classified leaks' and 'spying targeting Trump.'

Ukrainian Foreign Minister Vadym Prystaiko on Saturday denied in an interview with a Ukrainian news outlet suggestions that Trump had pressured Zelenskiy.

Biden, responding to a reporter's question at the Polk County Democratic Party's annual steak fry in Des Moines, denied that he had ever spoken to his son about his business dealings in Ukraine.

'You should be looking at Trump. Everybody looked at this and everybody who´s looked at it said there´s nothing there. Ask the right question,' continued Biden.

'You should be asking him the question: why is he on the phone with a foreign leader, trying to intimidate a foreign leader?'