US president Donald Trump has railed against special counsel Robert Mueller in a second day of angry tweets that drew comparisons to Watergate.

Mr Trump insisted his general counsel, Don McGahn, is not a “RAT”, and accused Mr Mueller’s team of “looking for trouble” in its probe into alleged Russian collusion.

The president tweeted: “If you FIGHT BACK or say anything bad about the Rigged Witch Hunt, they scream Obstruction!”

Mr Trump’s latest rant follows a New York Times report that the White House general counsel, Don McGahn, has been co-operating extensively with the special counsel team investigating Russian election meddling and potential collusion with Mr Trump’s Republican campaign.

In a tweet, the president contrasted Mr McGahn with John Dean, the White House counsel for Richard Nixon during the Watergate scandal.

Mr Dean ultimately cooperated with prosecutors and helped bring down the Nixon presidency in 1974, though he served a prison term for obstruction of justice.

Mr Trump wrote on Sunday: “The failing @nytimes wrote a Fake piece today implying that because White House Councel Don McGahn was giving hours of testimony to the Special Councel, he must be a John Dean type ‘RAT'”.

He added: “But I allowed him and all others to testify – I didn’t have to. I have nothing to hide …”

On Monday he called Mr Mueller “disgraced and discredited”.

He wrote: “Anybody needing that much time when they know there is no Russian Collusion is just someone looking for trouble.

“They are enjoying ruining people’s lives and REFUSE to look at the real corruption on the Democrat side – the lies, the firings, the deleted Emails and soooo much more!”

Mr Dean, ex-president Richard Nixon’s White House counsel and a frequent critic of Mr Trump, tweeted on Sunday that he doubts the president has “ANY IDEA what McGahn has told Mueller. Also, Nixon knew I was meeting with prosecutors, b/c I told him. However, he didn’t think I would tell them the truth!”

Mr Trump’s original legal team had encouraged Mr McGahn and other White House officials to cooperate with Mr Mueller, and Mr McGahn spent hours in interviews.

Mr Trump’s personal attorney, Rudy Giuliani, said in an appearance on NBC’s Meet the Press that Mr Trump did not raise executive privilege or attorney-client privilege during those interviews because his team believed – he says now, wrongly – that fully participating would be the fastest way to bring the investigation to a close.

Mr Giuliani said: “The president encouraged him to testify, is happy that he did, is quite secure that there is nothing in the testimony that will hurt the president.”

Rudy Giuliani
Mr Giuliani said ‘truth is not truth’ (AP)

Mr McGahn’s attorney William Burck added in a statement: “President Trump, through counsel, declined to assert any privilege over Mr McGahn’s testimony, so Mr McGahn answered the Special Counsel team’s questions fulsomely and honestly, as any person interviewed by federal investigators must.”

Mr Trump also assailed the Mueller investigation.

“So many lives have been ruined over nothing – McCarthyism at its WORST!” Mr Trump tweeted, referring to the indiscriminate and damaging allegations made by senator Joseph McCarthy in the 1950s to expose communists.

Mr Trump said later: “Study the late Joseph McCarthy, because we are now in period with Mueller and his gang that make Joseph McCarthy look like a baby! Rigged Witch Hunt!”

Mr Giuliani, in his interview, also acknowledged that the reason for the June 2016 Trump Tower meeting between Trump campaign aides and a Russian lawyer, arranged by Trump’s son Donald Trump Jr, was that they had been promised dirt on Mr Trump’s 2016 Democratic rival, Hillary Clinton.

“The meeting was originally for the purpose of getting information about Clinton,” he said, adding that the Trump team did not know that Natalia Veselnitskaya was Russian — even though emails later released by Trump Jr show that she had been described as a “Russian government attorney”.

Mr Giuliani also tried to make the case that having Mr Trump sit down for an interview with Mr Mueller’s team would not accomplish much because of the he-said/she-said nature of witnesses’ recollections.

“It’s somebody’s version of the truth, not the truth,” he said, telling NBC: “Truth isn’t truth.”