The Post, this week, reported that Robert Mueller, who is overseeing the FBI's probe into Russia's meddling in last year's United States presidential election and possible links with the Trump campaign, has expanded his inquiry to probe whether Trump obstructed justice by firing James Comey as Federal Bureau of Investigation chief.
It's a shift in the FBI investigation, which previously focused on Russian hacking during the election, possible coordination between the Trump campaign and Russian officials, and possible financial crimes by Trump associates.
Those who have agreed to be interviewed by Mueller's investigators, the Post reported, include Dan Coats, director of national intelligence; Mike Rogers, head of the National Security Agency; and Richard Ledgett, who recently left his role as Rogers' deputy.
Hours later, a source close to Mr Trump's outside legal team said Mr Trump did not intend his tweet to be confirmation of the investigation but rather was reacting to a Washington Post story on Wednesday about the probe.
Speaking to Harris Faulkner, Wallace said Trump once again kept Special Counsel Robert Mueller's investigation at the top of the headlines.
Rosenstein has said he is poised to recuse himself if he finds himself as a potential witness to Mueller's probe, meaning the top two officials at Justice would be on the sidelines for the Russian Federation investigation. "Witch Hunt", the president wrote in his tweet.
Trump's friend Christopher Ruddy says President 'considering' firing Mueller
Ruddy was at the White House to meet with White House aides but did not speak with the president, spokesman Sean Spicer said. He says he is confident that Mueller will have "the full independence he needs" to investigate thoroughly.
In another tweet Friday morning, Trump said it's "sad" that seven months of investigations and hearings into possible links between his campaign and Russian Federation have been fruitless.
"The FBI leak of information regarding the president is outrageous, inexcusable and illegal", Mark Carallo told the Washington Post".
In a flurry of tweets, Trump accused Mueller of being the one to tell him to fire Comey in the first place.
Why is Mr Trump being investigated?
Robert Mueller is seeking interviews with three Trump administration officials who weren't involved in Trump's campaign.
Moscow has denied USA intelligence agencies' conclusion that it interfered in last year's election campaign to try to tilt the vote in Trump's favor.