FILE - U.S. Attorney General William Barr arrives for U.S. President Donald Trump's State of the Union address to a joint session of the U.S. Congress in the House Chamber of the U.S. Capitol in Washington, Feb. 4, 2020.

U.S. Attorney General William Barr says President Donald Trump's tweets about the Justice Department, its people, and its cases "make it impossible for me to do my job."

This surprising statement from one of the president's most steadfast allies came Thursday, days after Barr's Justice Department overruled its own prosecutors and recommended a lighter prison sentence for longtime Trump friend Roger Stone, convicted of lying to Congress, witness tampering and obstruction of justice in the Russian election meddling probe.

FILE - Roger Stone, former campaign adviser to U.S. President Donald Trump, arrives for the continuation of his trial on charges of lying to Congress, obstructing justice and witness tampering, at U.S. District Court in Washington, Nov. 15, 2019.

Trump had complained that the seven-to-nine year recommended sentence was "horrible" and "unfair." The decision to recommend to the court giving Stone a lesser sentence came hours later. It is extremely rare for the Justice Department to overrule its own attorneys in a criminal case. The four prosecutors in the Stone case withdrew from case, including one who resigned from the department.

In an interview Thursday with ABC News, Barr said Trump has never asked him to "do anything in a criminal case."

"However, to have public statements and tweets about the department, about our people in the department ... about cases pending in the department and about judges before whom we have cases make it impossible for me to do my job and to assure the courts and the prosecutors in the department that we're doing our work with integrity," Barr told ABC.

"I'm not going to be bullied or influenced by anybody, whether it's Congress, a newspaper editorial board, or the president," Barr added.

After the recommended sentence for Stone was cut, Trump tweeted his congratulations to Barr for "taking charge of a case that was totally out of control and perhaps should not have been brought."

But Trump denied asking Barr to intervene.

Former campaign adviser for President Donald Trump, Roger Stone, arrives at Federal Court, Tuesday, Jan. 29, 2019, in Washington.
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The situation has brought into question the Justice Department's historic independence from any political influence. Democrats have called for an investigation into what prompted the recommendation of a lighter sentence for Stone. Barr is set to testify before a House committee next month.

The White house has yet to respond to Barr's comments about Trump's tweets.

Earlier Thursday, the president reposted a Fox News story accusing jurors in the Stone case of "political bias."

"This is not looking good for the Justice department," he wrote.

FILE - In this Nov. 15, 2019, file photo, Roger Stone, left, with his wife Nydia Stone, leaves federal court in Washington,…
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One of the jurors, Seth Cousins, told Reuters "it is appalling for the president of the United States to be attacking American citizens for patriotically fulfilling their duties." He said the new sentencing recommendation for Stone makes "It feel like something outrageous is going on."

Stone is a veteran political consultant who served as an adviser to a number of Republican presidential candidates going back to Richard Nixon's 1972 reelection campaign.

He is a close Trump ally and adviser. A jury convicted him in November on seven counts of lying to investigators, witness tampering, and obstruction stemming from special counsel Robert Mueller's investigation into whether the Trump campaign colluded with Russia to help Trump win the 2016 election.

Stone will be sentenced next week. The seven to nine years of prison prosecutors sought was based on federal sentencing guidelines for such crimes, but it will be up to the judge, Amy Berman Jackson, to decide how long he should be locked up.

Trump continued to complain about Stone's conviction in an interview with a Cleveland radio station Thursday.

"What am I going to do, sit back and let a man go to jail for maybe nine years when murderers aren't going to jail?" Trump asked.

He said the four Justice Department prosecutors who left the case did not leave for "moral reasons. I think they got caught in the act by me," he asserted.