President Donald Trump complained in a furious Friday morning tweet that he was being investigated for firing former FBI Director James Comey and seemed to accuse the deputy attorney general of overseeing a "witch hunt" against him.
"She added that she was "increasingly concerned" Mr Trump will fire both [investigative special counsel] Robert Mueller and Rosenstein".
A person who has spoken to Trump within the last 24 hours told CNN "the man" in the tweet is Rosenstein, who wrote a memo recommending Comey's firing and approved the appointment of a special counsel to look into Russian election meddling.
Trump's tweet that he is being investigated "by the man who told me to fire the FBI Director" may refer to Deputy Attorney General Rod Rosenstein. "You are witnessing the single greatest WITCH HUNT in American political history - led by some very bad and conflicted people!"
In an earlier tweet on Friday, Trump said, "After 7 months of investigations & committee hearings about my 'collusion with the Russians, ' nobody has been able to show any proof".
US President Donald Trump said that he was being investigated for his decision last month to fire the head of the Federal Bureau of Investigation, media reports said.
The special counsel is following two major lines of investigation, said one USA official familiar with the rough outlines of Mr Mueller's probe who spoke on condition of anonymity.
Mr Rosenstein has previously said that "if anything that I did winds up being relevant to his investigation then, as Director Mueller and I discussed, if there's a need from me to recuse, I will".
President Donald Trump is taking to Twitter denounce reports that the Russian Federation investigation is widening to examine whether he tried to obstruct justice.
"Why is that Hillary Clintons family and Dems dealings with Russian Federation are not looked at, but my non-dealings are?" the president tweeted.
The second, the official continued, is into whether if any potential offences were committed, Mr Trump or others attempted to cover them up or obstruct the investigation into them. The official claimed Trump was referencing the Washington Post's claims, which he said were based on "anonymous" and "illegal" leaks.
The order came the same day that Vice President Mike Pence hired an outside lawyer to represent his legal interests.
Pence retained Richard Cullen, a partner at McGuire Woods in Richmond, Virginia, who previously served as a USA attorney for the Eastern District of Virginia and has extensive experience with government investigations.
Mueller's investigation appeared to be reaching a broadening circle of current and former officials.
The Post and The New York Times both reported that Mueller was seeking interviews with three Trump administration officials who weren't involved in Trump's campaign: Dan Coats, the director of national intelligence; Michael Rogers, the head of the National Security Agency; and Richard Ledgett, the former NSA deputy director.
Comey declined Senate Judiciary Chairman Chuck Grassley's request to testify and went before the Senate Intelligence Committee instead.
The new allegations against Trump center on his own admission that he fired Comey because of the Russian Federation investigation, and suggestions he asked several top intelligence officials for their help altering the inquiry's direction.
Director of National Intelligence Dan Coats has met with the Senate Intelligence Committee for more than three hours in a closed session as part of the panel's probe into Russian interference in US elections.