"Witch Hunt", Trump stated in a Twitter message.
Your afternoon shot of politics, sent straight from the desk of Joshua Miller.
By some accounts, Trump's behavior has become increasingly volatile as the Mueller-led Russian Federation investigation expands.
Democrats and Republicans alike have criticised his use of Twitter, particularly amid the investigation into Russia's interference in last year's presidential election.
The President tweeted on Friday morning that he was "being investigated for firing the FBI Director by the man who told me to fire the FBI Director!".
The special counsel is following two major lines of investigation, said one USA official familiar with the rough outlines of Mueller's probe who spoke on condition of anonymity.
Donald Trump has appeared to confirm he is being investigated for obstruction of justice as he complained of a "witch hunt".
In his afternoon tweets, Trump picked up on that argument.
For months on end, the Albuquerque Journal/Associated Press have pushed the narrative that people associated with the Trump campaign were being investigated for colluding with the Russians. Page has deep experience with money laundering and organized crime cases, including investigations where she's partnered with an FBI task force in Budapest, Hungary, that focuses on eastern European organized crime.
A close Trump associate said this week the president was considering firing Mueller, although the White House later denied it.More news: Coach: Pakistan mindset better for CT final after India loss
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Trump tweeted on Thursday: "They made up a phony collusion with the Russians story, found zero proof, so now they go for obstruction of justice on the phony story".
"Despite high public interest in the content of the memos, Comey's testimony that the records are not classified and a ruling from the Justice Department that the Federal Bureau of Investigation should expedite CNN's FOIA request for the memos, the Federal Bureau of Investigation has not provided either the documents or a reason to withhold them", according to the lawsuit filed in the U.S. District Court for the District of Columbia.
Vice President Mike Pence hired an outside lawyer to represent his legal interests in the expanding Russian Federation probe. He is reportedly interviewing three top intelligence officials - Director of National Intelligence Dan Coats, National Security Agency Director Mike Rogers and retired deputy NSA director Richard Ledgett - as part of the probe as early as this week.
Even though Mueller is technically leading the investigation, the DOJ controls the funding for the investigation and can fire Mueller if the department decides it's warranted.
Investigators will also look for any statements the president may have made publicly and privately to people outside the government about his reasons for firing Comey and his concerns about the Russian Federation probe and other related investigations, people familiar with the matter said.
US Deputy Attorney General Rod Rosenstein issued a statement Thursday night that appeared to reference leaks and urged Americans to be skeptical of "stories attributed to anonymous 'officials'".
A spokesman for the office of the special counsel declined to comment, and so did a representative for the director of National Intelligence.
The RNC encouraged Trump allies to decry the "inexcusable, outrageous, and illegal" leaks on which it said the story was based and to argue that there is a double-standard at work.
The leaders of the Senate Intelligence committee said in a statement issued Wednesday that they "look forward to future engagements" with Robert Mueller.