Mr Trump tweeted: "I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director!"
Donald Trump has appeared to confirm he is being investigated for obstruction of justice as he complained of a "witch hunt". She's the associate attorney general, which makes her third in command at the Justice Department behind Rosenstein and Sessions. Mueller also has expansive powers to investigate any matters that develop from his initial investigation.
During congressional testimony last week, Comey stated under oath the President was not under investigation by the FBI prior to or after his firing.
"I would put that Rosenstein statement more in the "giving Trump enough rope" bucket than in the "succumbing to pressure" bucket", tweeted Matt Yglesias of Vox.
"If he fires Mueller, I will tell you, we are right on the brink of a constitutional crisis", the IL senator said.
"The message the president is sending through his tweets is that he believes the rule of law doesn't apply to him and that anyone who thinks otherwise will be fired", Feinstein said.
Roger Stone says President Trump should fire special counsel Robert Mueller and Deputy Attorney General Rod Rosenstein for "wasting the taxpayer's money" in what he called, a "witch hunt" to take down the president. Comey's firing likely will be part of that probe.
Trump lashes out at 'bad,' 'conflicted' Russia investigators
The tweet marked the first public, official confirmation that the president is under investigation for firing Comey in May. On Thursday, it was reported that President Trump himself was under investigation for possible obstruction of justice .
Trump had expressed the same outrage when Mueller, a former Federal Bureau of Investigation director from 2001 to 2013, was appointed last month by the US Department of Justice to probe Russian meddling. An official of Trump's transition confirmed the lawyer's internal order, which was sent Thursday. The official demanded anonymity because the official was not authorized to be named discussing the deliberations. Though Mr Pence was not involved in Mr Trump's presidential campaign, he may be called as a witness in the investigation into links between the Trump campaign team and Russian Federation.
The Post reports the other members include: 'former national security adviser Michael Flynn, former campaign chairman Paul Manafort and Carter Page, who was listed as a foreign-policy adviser for the campaign'.
While accusing the Clinton campaign and the Obama administration of indulging in illegal acts, Trump had said that "there was never a special counsel appointed to oversee the acts of his Democrat predecessors".
Mr Pence hired criminal lawyer Richard Cullen as special counsel Robert Mueller's investigation intensifies. Pence headed the Trump transition until inauguration day. The transition, a nonprofit structurally separate from the Trump campaign, continues to operate with a small staff.
"With this in mind please immediately suspend any deletion, modification, overwriting, or other possible destruction of the information described above, including electronic information, and take all reasonable measures to preserve this information", the memo said, according to the Times.
Meanwhile, members of Trump's transition team were ordered to preserve documents and other material related to the Russian Federation investigation, the New York Times reported.
"Why is that Hillary Clintons family and Dems dealings with Russian Federation are not looked at, but my non-dealings are?" he asked. "I can go around them", he tweeted.