Devin Nunes has been accused of abusing his office by issuing the release of the controversial FBI memo.

Former CIA Director John Brennan said the GOP lawmaker denied Democrats to their side of the story - something he described as 'appalling'.

He said the document was made public to 'protect' President Donald Trump amid the ongoing probe into Russian meddling during the Republican's successful race to The White House in 2016.

Democrats have chimed in on the argument over the weekend too, calling it a 'political hit job' and an attempt to 'undermine and discredit the FBI'.

Devin Nunes (pictured) has been accused of abusing his office by issuing the release of the controversial FBI memo

Former CIA Director John Brennan (pictured) said the GOP lawmaker denied Democrats to their side of the story - something he described as 'appalling'

Talking to NBC on their Meet The Press slot, Brennan said: 'I think it, it really underscores just how partisan Mr Nunes has been.

'He has abused the office of the chairmanship of HPSCI. And I don't say that lightly.'

Brennan - who served with the CIA under George W Bush and Barack Obama - added that Nunes 'has been engaged in these tactics purely to defend, make excuses and try to protect Mr Trump'.

Responding to the claims, which also included that Nunes had cherry-picked the memo to put aside a one-sided, selective memo, the lawmaker's spokesman said: 'There was an abuse of power, but it was not by the Chairman, who strictly followed House rules to make the Committee’s memo public.

'The abuse of power was the use of unverified information bought and paid for by one political campaign to justify government surveillance of associates of the opposing political campaign.'

The President's son, Donald Trump Jr, said the release of the memo was 'sweet revenge' for him and his family.

Talking to Fox News, he said document's release highlighted the collusion at the top of the FBI.

Brennan said the document was made public to 'protect' President Donald Trump (pictured) amid the ongoing probe into Russian meddling during the Republican's successful race to The White House in 2016

Democratic lawmakers have also weighed in on the argument, saying President Donald Trump was wrong to assert that a GOP-produced classified memo on FBI surveillance powers cleared him in the Russia investigation.

They expressed hope Sunday that special counsel Robert Mueller's work would continue without interference.

Democrats could seek a vote on publicly releasing their rebuttal memo when the GOP-led House Intelligence Committee meets late Monday afternoon.

The committee rejected that move last week, with one Republican member saying revisions were needed so the memo would not endanger national security.

The Senate's Democratic leader, Chuck Schumer of New York, urged Trump to back the public release and said that refusing to do so would show the president's intent to undermine the Russia investigation.

The committee's top Democrat, California Representative Adam Schiff, branded the GOP memo 'a political hit job'.

He questioned whether Nunes had coordinated with the White House in drafting the document seized on by the President to vent his grievances against the nation's premier law enforcement agencies.

'The goal here is to undermine the FBI, discredit the FBI, discredit the Mueller investigation, do the President's bidding,' Schiff said.

'I think it's very possible his staff worked with the White House.'

Nunes was asked during a January 29 committee meeting whether he had coordinated the memo with the White House.

'As far as I know, no,' he responded, then refused to answer when asked whether his staff members had communicated with the White House.

He had previously apologized for sharing with the White House secret intelligence intercepts related to an investigation of Russian election interference before talking to committee members.

The Senate's Democratic leader, Chuck Schumer of New York, urged Trump to back the public release and said that refusing to do so would show the President's intent to undermine the Russia investigation

The memo released Friday alleges misconduct on the part of the FBI and the Justice Department in obtaining a warrant under the Foreign Intelligence Surveillance Act to monitor former Trump campaign foreign policy adviser Carter Page and his ties to Russia.

Specifically, it takes aim at the FBI's use of information from former British spy Christopher Steele, who compiled a dossier containing allegations of ties between Trump, his associates and Russia.

The underlying materials that served as the basis for the warrant application were not made public in the GOP memo.

Even as Democrats described it as inaccurate, some Republicans quickly cited the memo - released over the objections of the FBI and Justice Department - in their arguments that Mueller's investigation is politically tainted.

The memo's central allegation is that agents and prosecutors, in applying in October 2016 to monitor Page's communications, failed to tell a judge that the opposition research that provided grounds for the FBI's suspicion received funding from Hillary Clinton's presidential campaign and the Democratic National Committee.

Page had stopped advising the campaign sometime around the end of that summer.

Steele's research, according to the memo, 'formed an essential part' of the warrant application. But it's unclear how much or what information Steele collected made it into the application, or how much has been corroborated.

Republicans say a judge should have known that 'political actors' were involved in allegations that led the Justice Department to believe Page might be an agent of a foreign power - an accusation he has consistently denied.

The memo confirms the FBI's counterintelligence investigation into the Trump campaign began in July 2016, months before the surveillance warrant was sought, and was 'triggered' by information concerning campaign aide George Papadopoulos. He pleaded guilty last year to lying to the FBI.

The confirmation about Papadopoulos is 'the most important fact disclosed in this otherwise shoddy memo,' Schiff said Saturday.

Schiff and Hurd spoke on ABC's 'This Week.' Stewart appeared on 'Fox News Sunday,' Gowdy was on CBS' 'Face the Nation' and Wenstrup was interviewed on CNN's 'State of the Union.'