Former Federal Bureau of Investigation Director James Comey told Congress last week he believed Trump fired him in May to undermine the agency's Russian Federation investigation.
Mueller is investigating Russian interference in USA elections and possible Russian ties to the Trump campaign.
PRESIDENT DONALD TRUMP: Oh, I was going to fire regardless of recommendation. Trump denies it even though he has the authority under the Constitution to fire Comey for any reason or no reason at all.
Trump's personal lawyer, Michael Cohen, also has retained an attorney to represent him.
Multiple committees in both houses of Congress are investigating the same thing.
Cohen has worked for Trump since the mid-2000s and was active in the campaign. He has already been subpoenaed by the House Permanent Select Intelligence Committee. He heads the McDermott, Will and Emery firm's government strategies practice. "Nice", Trump wrote in his first tweet.
Earlier this week, a friend of Trump said the president was considering it.
Trump is under increasing pressure on the Russian Federation probe.
Wednesday's session will focus on Russia's efforts to hack into state election systems, potential threats in upcoming election cycles, and whether states are well positioned to respond to those threats. Richard Burr, R-N.C., right, chairman of the Senate Select Committee on Intelligence, and Vice Chairman Mark Warner, D-Va., left, listen as Attorney General Jeff Sessions testifies before the Senate Select Committee.
This move toward possible obstruction charges by Mueller "marks a major turning point in the almost year-old FBI investigation, which until recently focused on Russian meddling during the presidential campaign and on whether there was any coordination between the Trump campaign and the Kremlin", wrote reporters at the Post. An official of Trump's transition confirmed the laywer's internal order sent Thursday.
The transition official spoke on condition of anonymity because the person was not authorized to discuss post-election decisions publicly. Pence headed the Trump transition until Inauguration Day.More news: Koepka wins first major championship at US Open
The Post reported that the obstruction of justice investigation of the president began days after James Comey was sacked as the FBI Director on May 9.
"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", he wrote on Twitter. It was not clear why he attributed the report to an Federal Bureau of Investigation leak.
That would be a freakish turn of events, given Rosenstein's role in justifying the Comey firing through a memo that faulted the ex-director's leadership.
The Washington Post reported Wednesday that special counsel Robert Mueller is seeking interviews with Coats and two other Trump administration officials and that the Russian Federation investigation is widening to examine whether President Donald Trump tried to obstruct justice.
If that is the case, it could be part of what appears to be a pattern of statements that are meant to back the president. "Regulations way down, jobs and enthusiasm way up!" That report was attributed to unnamed USA officials.
Trump and his supporters cast Comey's testimony that he had told the president he was not personally under investigation as vindication.
The president also appeared to undermine Mueller's leadership, saying the "witch hunt" was being "led by some very bad and conflicted people!"
Rosenstein told the Associated Press earlier this month that when he hired Mueller he discussed the possibility of having recuse himself "if anything that I did winds up being relevant to his investigation" and if recusal is necessary. He also has millions of followers on his official Facebook pages.
Not all of Trump's social media followers are supporters.
To pressure Trump, or possibly seek his removal, the Democrats, a section of the Republican Party and their media allies such as the New York Times and Washington Post are employing anti-democratic means, coordinating their moves with the spy agencies that carry out illegal surveillance of the American people and plot wars of aggression all over the world.
Trump has called The Washington Post report a "phony story" and a "WITCH HUNT". Last year, Democrats aggressively attacked Comey for his handling of the Hillary Clinton email investigation, with many calling for his firing.