Among the communications sought are those involving Paul Manafort, Trump's former campaign chairman whose work for a pro-Moscow Ukrainian political party drew scrutiny during the campaign, and Carter Page, a campaign advisor who took a trip to Moscow during the campaign, as well as fired national security advisor Mike Flynn.
Several White House officials and Trump associates insisted on anonymity in order to discuss the president's views of the unfolding investigation.
"Americans should exercise caution before accepting as true any stories attributed to anonymous 'officials, ' particularly when they do not identify the country - let alone the branch or agency of government - with which the alleged sources supposedly are affiliated". Americans should be skeptical about anonymous allegations. The Department of Justice has a long established policy to neither confirm nor deny such allegations.
Mr Mueller was appointed as special counsel to investigate Moscow's involvement in the presidential election a year ago and possible collusion by Trump campaign associates with the Russians, but there has been no indication that Mr Mueller told the president to fire Mr Comey.
The investigation appears to be reaching a broadening circle of current and former officials.
A person familiar with Trump's tweet said the President was referencing news reports that he is under investigation and was not indicating that he's been personally informed by the special counsel that he is a target of the probe.
Brand's resume includes work at private law firms including WilmerHale, the firm former FBI Director Robert Mueller left when he became special counsel in the Russian Federation probe.
Mr. Rosenstein took over the investigation into whether Russian Federation tried to tip the U.S election in favour of Mr. Trump after Attorney General Jeff Sessions recused himself in March. Mr Rosenstein wrote a memo criticising former Federal Bureau of Investigation chief James Comey's handling of the email server scandal that was initially used by the White House to justify the firing of Mr Comey.
Trump fired Comey on May 9, initially citing Rosenstein's memorandum, but later telling NBC News anchor Lester Holt that he always planned to fire Comey.
Bank of England policy split deepens as three officials seek rate hike
On the other hand, three members placed more weight on the pick-up of inflation and the diminished slack on the labor market. But the central bank said it was unclear how persistent this weakness would be, as consumer confidence remained solid.
After the firestorm caused by Comey's firing, Rosenstein appointed Mueller, Comey's predecessor as FBI director, to take over the DOJ Russia investigation.
In his tweet today, Trump seemingly confirmed the report and reiterated his charge linking his presidential campaign with Russian Federation is nothing but a political witch-hunt.
"The FBI leak of information regarding the president is outrageous, inexcusable and illegal", said Mark Corallo, the spokesman, according to the Post.
Sen. Dianne Feinstein, the top Democrat on the Senate Judiciary Committee, said she was "increasingly concerned" that Trump will fire both Mueller and Rosenstein.
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.
'We do not know what this report refers to, ' Jamie Gorelick said.
"What I did is I was going to fire Comey".
"The CIA does not, has not, and will never hide intelligence from the president, period".
That appeared to be the first public confirmation that Trump is being investigated for obstruction of justice - and a digital salvo trained at Deputy Attorney General Rod Rosenstein, who wrote a memo criticizing Comey.