And moments after he claimed on Twitter that he "had nothing to do with Russia helping me to get elected," the President in remarks to reporters at the White House reversed himself, freshly rejecting the idea of a Russian effort to boost his 2016 campaign -- another instance of him contradicting US intelligence findings.
"No, Russia did not help me get elected," Trump told reporters at the White House. "You know who got me elected? You know who got me elected? I got me elected. Russia didn't help me at all. Russia, if anything, I think, helped the other side."
The US intelligence community has assessed that Russia acted in 2016 to hurt former Secretary of State Hillary Clinton's campaign.
Trump's combative posture on Thursday morning left no doubt that Mueller's remarks and the growing calls for impeachment
that followed have rattled Trump.
Even as he privately indicated to allies that he would welcome an impeachment fight and believed the public would take his side, Trump recoiled with disgust at the mere mention of the topic.
"To me it's a dirty word, the word impeach. It's a dirty, filthy, disgusting word," Trump said.
While pressure has been steadily mounting on Democratic leaders to move toward impeachment, several Democrats seized on Mueller's decision to highlight a constitutional "process other than the criminal justice system to formally accuse a sitting president of wrongdoing" -- impeachment -- in his Wednesday remarks. To several key Democrats, Mueller was referring his case over to the House for impeachment proceedings.
Trump, as he often does, initially offered a relatively muted response to Mueller's statement on Wednesday -- at one point tweeting simply that there was "insufficient evidence" to prosecute him.
But by Thursday morning he was full of indignation over the investigation and the rising drumbeat of impeachment talk.
Even as Trump slammed Mueller and his team of career prosecutors, the President claimed exoneration thanks to Mueller's decision not to make a determination on whether Trump had committed a crime.
"There were no charges. None," Trump said, arguing the result is that he is "innocent of all charges."
Mueller, though, made clear he had not made a determination because of an Office of Legal Counsel opinion preventing a sitting President from being charged with a crime, and because it would be "unfair" to accuse the President of a crime when there can be no legal resolution while he is in office.
Trump repeated that he was "innocent of all charges" and "there was no crime" before telling reporters to read Article Two of the Constitution, which outlines the powers of the presidency.
"Someday, you oughta read a thing called Article Two. Read Article Two, which gives the President powers you wouldn't believe, but I don't even have to rely on Article Two. There was no crime, there was no obstruction no obstruction, there was no collusion, there was no nothing," Trump said.
Earlier Thursday morning, Trump acknowledged on Twitter Russia's efforts to interfere in the 2016 election to aid his campaign before walking back the statement to reporters.
"Russia, Russia, Russia! That's all you heard at the beginning of this Witch Hunt Hoax...And now Russia has disappeared because I had nothing to do with Russia helping me to get elected. It was a crime that didn't exist," Trump wrote in a tweet.
Trump has frequently denied that Russia interfered in the election to help him, a position that stands at odds with the US intelligence community's assessment of Russia's actions in 2016.
The US intelligence community has said the Russians did not change vote totals. It is not possible to assess the impact of their efforts on voters' opinions and behaviors.
CNN's Betsy Klein and Marshall Cohen contributed to this report.