President Donald Trump launched a fierce new attack Tuesday against Russia collusion investigator Robert Mueller, pumping up the political tensions as the probe increasingly menaces the White House.
In some of his strongest language yet against the investigation he has long labelled a "witch hunt,' the US president called Mueller "a conflicted prosecutor gone rogue."
"He is doing TREMENDOUS damage to our Criminal Justice System," Trump charged in a series of tweets.
The attack on the special counsel came a day after Mueller halted a cooperation deal with Trump's former campaign chairman Paul Manafort, accusing him of lying to investigators.
The allegations against Manafort came the same day George Papadopoulos, a foreign affairs advisor to Trump's 2016 campaign, was imprisoned for two weeks for lying to investigators about his Russian contacts -- more than a year after pleading guilty in one of the first cases brought by the special counsel.
Both moves added to speculation that Mueller is getting closer to wrapping up his 18-month-old probe -- potentially bringing charges related to collusion between Trump's campaign and a Russian effort to tilt the 2016 vote, or to an alleged attempt by Trump to obstruct the probe itself.
Last week the White House revealed that Trump had answered a long list of questions submitted by Mueller's team early this year, ending a lengthy delay that fueled speculation that Trump could be subpoenaed to testify.
The lying claims against Manafort have reinforced the belief Mueller is drawing closer to concluding the main part of his investigation, with the White House in his sights.
On Tuesday the Guardian newspaper injected an incendiary new detail into the case, if it is true.
It reported that Manafort met WikiLeaks founder Julian Assange in March 2016 just weeks before the group began publishing documents embarrassing to Trump rival Hillary Clinton, documents that Washington says were stolen and disseminated by Russian intelligence.
Manafort and WikiLeaks both strongly denied the report.
"This story is totally false and deliberately libelous. I have never met Julian Assange or anyone connected to him. I have never been contacted by anyone connected to WikiLeaks, either directly or indirectly," Manafort said in a statement.
At the same time, the Mueller team has been investigating two other people linked to the Trump campaign, consultant Roger Stone and conservative media activist Jerome Corsi, over their contacts with WikiLeaks in 2016.
Corsi told reporters Monday he expects to be indicted after rejecting a plea deal.
Mueller, a former FBI director, remains tight-lipped about his sprawling investigation, which has so far given rise to three dozen indictments and guilty pleas and convictions in nine cases.
His team remains under threat from Trump, whose new acting attorney general, Matthew Whitaker, appears to have been chosen in part for his public hostility to Mueller, who he will now oversee.
Trump has repeatedly branded the investigation "illegal" and has insisted there was no cooperation with Russia.
Trump "was involved in no wrongdoing, was not part of any collusion," White House spokeswoman Sarah Sanders said Tuesday.
Democrats and some Republicans in Congress have pressed for legislation to prevent Trump and Whitaker from shutting the investigation down.
Yet court filings indicate it is fairly advanced, with a focus on whether there is enough evidence in multiple contacts between Trump campaign aides and Russians to support charges of a criminal conspiracy to disrupt the US election.
Mueller is also examining possible obstruction by Trump, a charge that could expose the president to an impeachment motion in Congress.