The president's tweet represents the latest escalation in a controversy regarding the case against Roger Stone, Trump's longtime informal political adviser, that has consumed the Justice Department and provoked a rare display of public disapproval by Barr toward his boss.

"I think it's time to stop the tweeting about Department of Justice criminal cases," the attorney general told ABC News.

Barr's rebuke of Trump's online conduct came after the president tweeted his displeasure Tuesday with federal prosecutors' seven-to-nine-year sentencing proposal for Stone.

Following Trump's criticism, the Justice Department submitted a revised filing that offered no specific term for Stone's sentence but stated that the prosecutors' initial recommendation “could be considered excessive and unwarranted."

The four government attorneys who had shepherded Stone's prosecution then withdrew from the case in protest.

Trump congratulated Barr in a tweet Wednesday for "taking charge" of the Stone case, and thanked the Justice Department from the Oval Office for stepping in to stop "this horrible thing."

Barr confirmed 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.

"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."

Although Barr's statements could be viewed as a sign of heightened tensions between the president and his attorney general, White House press secretary Stephanie Grisham claimed Thursday that Trump was not irked by Barr‘s interview.

"The President wasn't bothered by the comments at all and he has the right, just like any other American citizen, to publicly offer his opinions," she said. "President Trump uses social media very effectively to fight for the American people against injustices in our country, including the fake news. The President has full faith and confidence in Attorney General Barr to do his job and uphold the law."

Some Democratic lawmakers, however, have speculated that Barr's admonishment of Trump was a calculated maneuver aimed at quelling outrage within his department, rather than a genuine plea meant to curb the president's behavior.

A Justice Department official confirmed Friday that Barr recently dispatched the U.S. Attorney for Eastern Missouri, Jeff Jensen, to aid in a review of the history of the prosecution of former Trump National Security Adviser Michael Flynn. Jensen’s role is to conduct a top-to-bottom review of allegations of misconduct from Flynn’s defense team in conjunction with Brandon Van Grack, the former Mueller aide who has shepherded the case from its outset, according to the source.

Still, Flynn’s effort to unwind his guilty plea appears to be an uphill battle, since the retired Army general and Defense Intelligence Agency chief confirmed his guilt under oath to two different federal judges.

This week, Van Grack filed a response in court rejecting the defense’s claims that outrageous conduct by investigators and prosecutors so tainted the case that it should be thrown out. However, the filing seemed to leave open the possibility that prosecutors might identify more evidence favorable to Flynn.

“The government is aware of its ongoing discovery and disclosure obligations, and continues to review information that arguably could be pertinent to the defendant’s guilt or punishment with those obligations in mind,” Van Grack wrote.

Barr, who installed Van Grack last year in a newly-created Justice Department post overseeing foreign-agent enforcement, still has confidence in the former Mueller prosecutor, two Justice officials said.

Barr's interview and subsequent actions have done nothing to extinguish Democrats' calls for his resignation. Nine senators, including presidential candidates Elizabeth Warren (D-Mass.) and Bernie Sanders (I-Vt.), sent a letter to the attorney general Friday demanding that he step down.

"While you asserted yesterday in an interview with ABC News that you were 'not going to be . . . influenced by anybody,'" the senators wrote to Barr, "this statement is simply not credible given that it is sharply at odds with the behavior of top DOJ officials and the comments of the President over the past 72 hours."

Amid the pushback against Trump from the uppermost rungs of the Justice Department, Sen. Lindsey Graham (R-S.C.) — who has fashioned himself into one of the president's staunchest allies — announced Friday a long list of interview requests with top FBI and DOJ officials as part of an investigation into the origins of the 2016 Russia investigation known as "Crossfire Hurricane."

In a letter to Barr, Graham said he is seeking transcribed interviews with case agents and senior Justice Department figures involved in that probe, as well as a slew of former officials. Among the requests: top FBI official Dana Boente and DOJ official Bruce Ohr.

Kyle Cheney and Josh Gerstein contributed to this report.