WASHINGTON (AP) - Vowing "I will not be bullied," President Donald Trump's nominee for attorney general asserted independence from the White House on Tuesday, saying he believed that Russia had tried to interfere in the 2016 presidential election, that the special counsel investigation shadowing Trump is not a witch hunt and that his predecessor was right to recuse himself from the probe.

The comments by William Barr at his Senate confirmation hearing pointedly departed from Trump's own views and underscored Barr's efforts to reassure Democrats that he will not be a loyalist to a president who has appeared to demand it from law enforcement. He also repeatedly sought to assuage concerns that he might disturb or upend special counsel Robert Mueller's investigation as it reaches its final stages.

Some Democrats are concerned about that very possibility, citing a memo Barr wrote to the Justice Department before his nomination in which he criticized Mueller's investigation for the way it was presumably looking into whether Trump had obstructed justice.

Sen. Dianne Feinstein of California, top Democrat on the Senate Judiciary Committee, told Barr the memo showed "a determined effort, I thought, to undermine Bob Mueller." The nominee told senators he was merely trying to warn Justice Department officials against "stretching a statute" to conclude that the president had obstructed justice.

Though Barr said an attorney general should work in concert with an administration's policy goals, he broke from some Trump talking points, including the president's mantra that the Russia probe is a witch hunt. Trump has equivocated on Russian meddling in the 2016 presidential election and assailed and pushed out his first attorney general, Jeff Sessions, for recusing because of his work with the Trump campaign.

Barr stated without hesitation that it was in the public interest for Mueller to finish his investigation into whether the Trump campaign coordinated with the Kremlin to sway the election. He said he would not fire Mueller even if Trump asked him to do it and called it "unimaginable" that Mueller would do anything to require his termination.

"I believe the Russians interfered or attempted to interfere with the election, and I think we have to get to the bottom of it," Barr said.

Positioning himself as independent from the president, he said that, at 68 years old and partially retired, he felt emboldened to "do the right thing and not really care about the consequences."

"I will not be bullied into doing anything that I think is wrong by anybody, whether it be editorial boards or Congress or the president," Barr told the hearing.

Barr's confirmation is likely, given that Republicans control the Senate. Even some Democrats have been looking to move on from acting Attorney General Matthew Whitaker, who declined to remove himself from matters involving the Russia probe and has faced scrutiny over his private dealings.

But he nonetheless faced skeptical questions from Democrats over whether he could oversee without bias or interference the remainder of Mueller's probe.

Feinstein said the nominee's past rhetoric in support of expansive presidential powers "raises a number of serious questions about your views on executive authority and whether the president is, in fact, above the law."

Barr called Mueller a friend of 30 years and said he would not undermine his work. He said he would consult with ethics officials on whether he would need to recuse because of the memo but the decision would be ultimately his.

"I don't believe Mr. Mueller would be involved in a witch hunt," he said when asked by the panel's Republican chairman, Sen. Lindsey Graham of South Carolina.

He also disclosed having discussed Mueller with Trump during a meeting in 2017 when Barr declined to join his legal team. Trump wanted to know what Mueller, who worked for Barr when he led the Justice Department between 1991 and 1993, was like.

"He was interested in that, wanted to know what I thought about Mueller's integrity and so forth and so on," Barr told senators. "I said Bob is a straight shooter and should be dealt with as such."

Barr also said "it is vitally important" that Mueller be allowed to complete his investigation and that Congress and the public should learn the results. He insisted that Trump never sought any promises, assurances or commitments before selecting him for the job and said he had never asked him to fire Mueller or interfere with the investigation.

He also defended his decision to send an unsolicited memo to the Justice Department criticizing Mueller's investigation into whether the president had sought to obstruct justice. He said he raised his concerns at a lunch last year with the deputy attorney general, Rod Rosenstein, who appointed Mueller and oversees his work. Rosenstein did not respond and was "sphinx-like," Barr recalled. He followed up with the memo in June.

Barr also sent the memo to White House lawyers and discussed it with Trump's personal attorneys and a lawyer who represents Trump's son-in-law, Jared Kushner, among others.

In it, he criticized as "fatally misconceived" the theory of obstruction that Mueller appeared to be pursuing. He said presidents cannot be criminally investigated for actions they are permitted to take under the Constitution, such as firing officials who work for them, just because of a subjective determination that they may have had a corrupt state of mind.

Barr said the memo was narrowly focused on a single theory of obstruction that media reports suggested Mueller might be considering.

"The memo did not address - or in any way question - the special counsel's core investigation into Russian interference in the 2016 election," Barr said.

The special counsel is required to report his findings confidentially to the Justice Department. Barr stopped short of directly pledging to release Mueller's report but expressed general support for disclosing the findings.

"That certainly is my goal and intent," he said.