"This is the single greatest witch hunt of a politician in American history!" he said. "And hopefully, this can go quickly, because we have to show unity if we're going to do great things with respect to the rest of the world".
Trump's early morning tweet storm comes day after his Justice Department appointed former FBI Director Robert Mueller as special counsel to oversee the the agency's Russian Federation investigation, a decision the president appeared to accept after it was announced.
The U.S. Justice Department has appointed former FBI director Robert Mueller as special counsel to oversee the agency's investigation into alleged meddling by Russian Federation in the 2016 presidential election and possible collusion between the Kremlin and President Donald Trump's campaign. As special counsel, Mueller will be able to [BBC report] issue subpoenas, bring criminal charges, and can prosecute anyone who interferes in his investigation through crimes including perjury, destruction of evidence, obstruction of justice, and intimidation of witnesses. "I now have significantly greater confidence that the investigation will follow the facts wherever they lead".
Mueller, a former federal prosecutor at the Justice Department, was confirmed as FBI director days before the September 11, 2001, attacks that would ultimately shape his tenure.
Asked if he had done anything that might merit prosecution or even impeachment, Mr Trump said "no" and then added of the lingering allegations and questions: "I think it's totally ridiculous".
"Why no special counsel was appointed for what he called all of the illegal acts of Hillary Clinton's campaign and the Obama administration", Trump said.More news: Ransomware cyber-attack threat escalating
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The president repeated his belief that the controversy over the interference and possible collusion between Russian Federation and the Trump campaign was baseless. "No politician in history has been treated worse or more unfairly". It may also be seen as an attempt to discredit the inquiry before it starts or to prejudge its results.
The tweets fly in the face of the statement issued on Wednesday night which had appeared as an attempt by Trump's staff to tamp down the raging political storm over Russian Federation which has resulted in Trump's worst week in office so far.
The broad mandate, beyond any specific Trump-Russia connection, also covers "any matters that arose or may arise directly from the investigation".
"I expected him to be ranting and raving, but he was like, 'Fine, let them do what they have to do, but we'll be focused on our agenda, '" said this official, who requested anonymity to describe the private talks.
Trump reiterated his innocence on Wednesday, saying in a statement that a "thorough investigation will confirm what we already know - there was no collusion between my campaign and any foreign entity". Democratic senators had been prepared to press him to appoint a special prosecutor, and his decision defused their complaints, leading to praise instead. Trump later deleted and retweeted that statement to correct the spelling of "counsel".
Earlier Thursday, Trump blasted the probe as the "greatest witch hunt" in U.S. political history.