The president went on to accuse Mueller of lying before Congress when he told lawmakers he did not interview with Trump to apply for the job of FBI director, tweeting: "The whole deal was a total SCAM. If I wasn't President, I'd be suing everyone all over the place. BUT MAYBE I STILL WILL. WITCH HUNT!"

Trump's posts came on a whirlwind Tuesday during which the president declared himself the country's "chief law enforcement officer," insisted on his right to meddle in criminal cases involving his close associates, announced a spate of controversial pardons and commutations, and acknowledged that he was making his own attorney general's job harder.

The president's legal threats represent the latest development in his renewed assault against Mueller, which escalated last week after Trump expressed his disapproval of federal prosecutors' initial sentencing recommendation for Stone.

The former special counsel's work led to Stone's arrest in January 2019 and indictment on seven felony charges. Two of the attorneys who prosecuted Stone's case had previously served on Mueller's team of investigators. A Washington jury found Stone guilty on all counts in November.

After Trump tweeted last Tuesday that prosecutors' suggested seven-to-nine-year sentence for Stone was a "miscarriage of justice," the Justice Department submitted a revised filing that offered no specific term for Stone's sentence but stated that the prosecutors' proposal "could be considered excessive and unwarranted." The four attorneys who had shepherded Stone's prosecution then withdrew from the case in protest.

Attorney General William Barr confirmed in an interview Thursday that he had personally interceded to walk back Stone's stiff sentencing recommendation, but maintained that he did so hours before Trump tweeted his objection. Barr also called upon the president "to stop the tweeting about Department of Justice criminal cases" and urged him to curb his social media activity.

"To have public statements and tweets about the department, about people in the department, our men and women here, about cases pending in the department, about judges before whom we have cases," Barr said, makes it "impossible for me to do my job and to ensure the courts and the prosecutors and department that we're doing our work with integrity."

Despite the attorney general's scolding, Trump tweeted Friday that he has the "legal right" to demand that Barr take action in a federal criminal case, and he proceeded in his tweets Tuesday to denigrate the "Mueller prosecutors" assigned to Stone's case.

Addressing reporters on Tuesday afternoon at Joint Base Andrews, the president defended his Twitter use while carefully sidestepping any direct criticism of his attorney general.

"Everybody has the right to speak their mind," Trump said of Barr, conceding that "I do make his job harder. I do agree with that. I think that's true. He's a very straight shooter. We have a great attorney general, and he is working very hard."

Trump also labeled himself the "chief law enforcement officer of the country" — a title typically reserved for the attorney general — and said he is "allowed to be totally involved" in Justice Department affairs. He added, however, that "I've chosen not to be involved."

Top congressional Republicans on Tuesday joined Trump in praising Barr, with Senate Majority Leader Mitch McConnell (R-Ky.), House Minority Leader Kevin McCarthy (R-Calif.) and Senate Judiciary Chairman Lindsey Graham (R-S.C.) describing him as a "man of the highest character and unquestionable integrity."

"Suggestions from outside groups that the Attorney General has fallen short of the responsibilities of his office are unfounded. The Attorney General has shown that he is committed without qualification to securing equal justice under law for all Americans," the lawmakers said in a statement, adding: "We expect that, as always, efforts to intimidate the Attorney General will fall woefully short."

Apart from Mueller, the president on Tuesday also invoked on Twitter U.S. District Judge Amy Berman Jackson, who is scheduled to sentence Stone on Thursday and has overseen several other Mueller-related cases.

Seemingly quoting remarks by Fox News' Andrew Napolitano in a series of tweets, Trump sought to pressure Jackson to honor Stone's bid for a new trial, disclosed in a court order Friday. Jackson on Sunday ordered the defense and the prosecution in the Stone case to participate in a telephone hearing Tuesday to discuss the case's status.

Meanwhile, the national Federal Judges Association has reportedly called an emergency meeting for sometime this week to address mounting concerns over Trump's and Barr's interventions in politically sensitive cases. White House press secretary Stephanie Grisham on Tuesday defended the president's commentary on Justice Department affairs.

"The president has made clear his position on many different cases, but he leaves AG Barr to do his work. He's made it clear that the two things are separate," she told Fox News in an interview Tuesday morning. "But the president will always, always tell the American people what his opinion is."

Pressed on the president's tweets Tuesday and his reference to potential legal action, Grisham described him as "frustrated" and promoted news reports of alleged anti-Trump bias by the forewoman of the federal jury that heard Stone's case.

"This is just another example of the constant barrage of corruption that has gone against this president. And of course, despite that, he continues to do great things," she said. "But he's frustrated, obviously, and who knows what he'll end up doing."

Trump has wielded litigation as a cudgel for decades over the course of his real estate career, and has continued to threaten lawsuits against perceived political enemies during his time in office — many of which have fizzled out.

Myah Ward contributed to this report.