Attorney General Bill Barr told lawmakers Tuesday he was 'reviewing' the conduct of the FBI at the start of the Russia probe – an investigation that powerful Republicans including President Trump have demanded.

Barr provided the information during testimony where he also revealed he will make public a redacted version of the Mueller report within a week.

'I am reviewing the conduct of the investigation and trying to get my arms around all the aspects of the counterintelligence investigation that was conducted during the summer of 2016,' Barr said at a subcommittee hearing Tuesday.

Barr revealed his top-level review under questioning by top Appropriations subpanel Republican Rep. Robert Aderholt of Alabama.

The lawmaker was asking the attorney general about former House Intelligence Chairman Rep. Devin Nunes making criminal referrals to DOJ about leaks and other alleged misconduct by the FBI at the start of the Russia probe.

Although such referrals do not have the power to force an investigation, Nunes said they pertained to 'alleged misconduct during the Russia investigation including the leak of classified material and alleged conspiracies to lie to Congress and the FISA court in order to spy on then-candidate Trump and other persons.'

Aderholt told DailyMail.com that he had not had any additional back-channel conversations with the Justice Department to confirm the extent of the review Barr is conducting.

'I got the impression that [the matter] was on his radar screen that he was looking at it in a very close manner,' Aderholt said. 'I would think in this day and age that when it’s regarding the dossier issue, that’s been a big topic and I think he knows all about it.'

President Trump has repeatedly branded the Mueller probe a 'witch hunt' and said after the release of Barr's letter the conduct by FBI investigators should be looked at. The president repeatedly taunted Barr's predecessor, Jeff Sessions, for recusing himself from the Russia probe.

Senate Judiciary Chairman Lindsay Graham (R-S.C.) is conducting his own investigation of the origins of the probe, while also probing the FBI's 2016 Clinton email investigation.

In another key developing Tuesday, Barr said he was sticking to a proposed timeline, an indication that he has made progress in vetting information for redactions from what he will allow to be released.

'From my standpoint, within a week, I will be in a position to release the report to the public and then I will engage with the chairmen of both Judiciary Committees about that report,' Barr testified Tuesday.

But lawmakers at a House subcommittee hearing grilled him about the redactions he would make to the report, and tried to pin him down on what material he would withhold – as well as whether he would ever reveal why it got excised.

Attorney General William Barr testified he should be in a position to release the redacted Mueller report 'within a week'

'We will color-code the excisions from the report and we will provide explanatory notes describing the basis for each redaction,' Barr said, who said Mueller's team was participating in the redactions.

He said there were four categories of redactions: information presented to grad juries; passages which would reveal intelligence sources and methods; details of ongoing prosecution cases; and information about 'incidental parties' which could harm their 'privacy and reputational interests.'

And Barr also flatly told Democrats that he will not hand over the entire report and its underlying evidence, setting up a major battle with Congress over Mueller.

His appearance in front of one of the House Appropriations Committee subcommittees was the first time he has answered questions on Mueller - but he repeatedly refused to offer any insight into its contents.

Barr would not also directly answer a question about whether the White House had seen the Mueller report, was briefed in advance of Barr's letter, or had been briefed on its contents.

'I've said what I'm going to say about the report today,' said Barr. 'I've issued three letters about it. And I was willing to discuss the historic information of how the report came to me and my decision on Sunday,' Barr said.

'But I've already laid out the process that is going forward to release these reports hopefully within a week, and I'm not going to say anything more about it until the report is out and everyone has a chance to look at it,' he continued.

He also wouldn't directly respond to a question about whether President Trump was accurate when he said the report was a 'complete and total exoneration' of him.

Appropriations Committee Chair Nita Lowey of New York pointed to a passage in his letter stating that Mueller and his team included information on both sides of whether the president could potentially be charged with obstruction of justice.

'I'm not going to discuss it any further until after the report is out,' Barr responded.

Barr described a process for putting out the report that could occur in two phases. Next week, he plans to release to the public a report with the redactions he has discussed. He told Lowey he would not put out the unredacted version.

HAVE A SEAT: Barr fielded questions about redactions, and whether the White House had seen the report. He wouldn't answer that question directly

Democrats accuse Barr of watering down Mueller's conclusions in his four-page letter

Barr faced tough questioning about President Trump's claim the report exonerated him, and whether the White House had been briefed on the report

'No, the first pass at this is going to produce a report that makes these redactions based on these four categories' described in a letter to Congress. Then, he said, he would consult with the chairmen of the House and Senate Judiciary Committees to see 'whether they need more information and see if there's a way we could accommodate that.'

Barr told lawmakers he was operating under regulations that govern the circumstances for transmitting a special counsel report to Congress.

'I am relying on my own discretion to make as much public as I can,' he told them.

'I do think it's important that the public have an opportunity to learn the results of the special counsel's work,' said Barr.

Rep. Charlie Crist (D-Fla.) asked Barr about a line he included in his letter about the report, that it 'does not exonerate' the president of obstruction.

His response was terse. 'I think that’s the language from the report,' Barr said.

'That’s a statement made by the special counsel. I report it as one of his bottom-line conclusions. So I’m not in a position to discuss that further until the report is all out. And then what is meant by exonerate is not really a question that I can answer – what he meant by that,' Barr continued.

Crist asked him: 'As you sit here today you can’t opine after having read the report yourself, why it reaches that conclusion that it does not exonerate the president?'

'That’s right,' said Barr.

The exchange was one of several during Tuesday's hearing that included long periods of silence, as lawmakers expected Barr to say more.

House Democrats got their first chance at the hearing to grill Barr point-blank about why he cranked out a four-page summary of the Mueller report just 48 hours after he got it – and whether he softened its conclusions.

Rep. Jose Serrano, a House subcommittee chairman, raised the issue of the 'elephant in the room' at the start of a high-stakes hearing.

He said lawmakers had 'serious concerns about the process by which you formulated your letter and uncertainty about when we can expect to see the full report.'

Barr was asked about President Trump's claim that the report was a complete and total exoneration of him

'I believe the American people deserve to see the full report,' said Serrano. Serrano noted that Congress voted unanimously to see the full Mueller report.

'We're not here today to be in a confrontational situation with you,' said Serrano. 'What cannot happen is that somebody higher than you tells you that you don't have to answer our questions or you don't have to deal with us at all. That's not who we are as a country,' he said

Full Committee chair Rep. Nita Lowey blasted Barr's letter early in the hearing.

'We have no idea how long [the report] actually is' she fumed. 'All we have is your four page summary which seems to cherry pick from the report, to draw the most favorable conclusion possible for the president.'

She said of the letter Barr turned around in just 48 hours: 'Even for someone who has done this job before, I would argue it's more suspicious than impressive.'

Barr, who faces lawmakers for the first time since taking office – also is set to get peppered with questions about the recusal process he is overseeing to determine what parts of the 400-page Mueller report he may withhold from lawmakers and from the public.

Barr has set up four categories of information he intends to vet to see whether it should be held back – prompting Democrats to demand he release the entire, un-redacted report that Special Counsel Robert Mueller assembled over two years with a budget of tens of millions.

In his first appearance on Capitol Hill since taking office, Attorney General William Barr arrives to appear before a House Appropriations subcommittee to make his Justice Department budget request

In addition to screening for grand jury material that by law is not to be made public, Barr wrote Congress that he would vet the Mueller report for information that would impact 'reputational interests.'

Barr isn't coming to Congress to talk about the report, but lawmakers are expected to ask about it anyway as they anxiously wait to see it in the coming days.

The topic of the House appropriations subcommittee hearing is the Justice Department's budget, and Barr's prepared remarks sent to the committee on Monday focused on funding requests for immigration enforcement and to combat violent crime and opioid addiction, not mentioning Mueller's report at all.

He appeared before the House Appropriations Commerce, Justice, Science, and Related Agencies Subcommittee

Mueller sent his final report to Barr on March 22, ending his almost two-year investigation into potential ties between the Trump campaign and Russia.

Barr released a four-page letter summarizing the report two days later and said he would release a redacted version of the full report by mid-April, 'if not sooner.'

The new attorney general's budget testimony - traditionally a dry affair, and often addressing the parochial concerns of lawmakers - comes as Democrats are enraged that Barr is redacting material from the report and frustrated that his summary framed a narrative about President Trump before they were able to see the full version.

The Democrats are demanding that they see the full report and all its underlying evidence as Trump and his Republican allies are pushing back.

In excerpts from her opening statement released Monday night, House Appropriations Committee Chairwoman Nita Lowey, D-N.Y., said that Barr's summary letter 'raises more questions than it answers.'

The chairman of the subcommittee, Democratic Rep. Jose Serrano of New York, also said there were unanswered questions, including 'serious concerns about the process by which you formulated your letter; and uncertainty about when we can expect to see the full report.'

Barr said in the summary released last month that Mueller didn't find a criminal conspiracy between the campaign and the Kremlin.

He has also said that Mueller did not reach a conclusion on whether the president obstructed justice, instead presenting evidence on both sides of the question.

Barr said he and Deputy Attorney General Rod Rosenstein decided that the evidence was insufficient to establish obstruction.

Facing the intensifying concerns from Democrats that he may have whitewashed Mueller's findings, Barr has twice moved to defend, or at least explain, his handling of the process since receiving the special counsel's report.

He has said that he did not intend for his four-page summary of Mueller's main conclusions to be an 'exhaustive recounting' of his work and that he could not immediately release the entire report because it included grand jury material and other sensitive information that needed to first be redacted.

Trump tweeted: 'The Democrats will never be satisfied, no matter what they get, how much they get, or how many pages they get. It will never end, but that's the way life goes!'

The president attacked Mueller and his 'team of 13 Trump haters and angry Democrats' for 'illegally leaking information to the press'

He will likely be asked to further explain himself at the hearing Tuesday and at a Senate appropriations subcommittee hearing Wednesday that is also on the budget.

Barr is scheduled to testify on the report itself at separate hearings before the Senate and House judiciary committees on May 1 and May 2.

Rep. Jerrold Nadler, a New York Democrat and chairman of the House judiciary panel, confirmed the May 2 date on Twitter and said he would like Mueller to testify.

Senate Judiciary Committee Chairman Lindsey Graham, R-S.C., has said he would be satisfied hearing only from Barr and not Mueller.

While Trump took a victory lap after Mueller concluded his Russia investigation, it now appears to have been premature.

The scramble to frame the investigation's findings in the best political light is sure to be renewed in coming days when Mueller's report is expected to be released in redacted form.

Now that the American public will get a look at details beyond the four-page investigation summary written by William Barr, some Trump allies are concerned that the president was too quick to declare complete triumph and they're pushing the White House to launch a pre-emptive attack.

Trump seems to be of the same mind.

'The Democrats will never be satisfied, no matter what they get, how much they get, or how many pages they get,' Trump tweeted Monday, two days after he blasted 'Bob Mueller's team of 13 Trump Haters & Angry Democrats.'

READ IN FULL: Attorney General Barr's letter to Congress summarizing the Mueller investigation findings Advertisement

With the goal to discredit what's coming, Trump and his allies have unleashed a series of broadsides against Mueller's team and the Democrats pushing for full release of the final report.

No longer is the president agreeing that Mueller acted honorably, as he did the day after the special counsel's conclusions were released.

Instead, he's joining his allies in trying to undermine the integrity of the investigators and the credibility of their probe.

'You're darn right I'm going after them again,' Rudy Giuliani, one of Trump's attorneys, told The Associated Press.

'I never thought they did their job in a professional manner. ... Only because there is overwhelming evidence that the president didn't do anything wrong, they were forced to admit they couldn't find anything on him. They sure tried.'

While the president unleashed his personal grievances, his team seized on any exculpatory information in Barr's letter, hoping to swiftly define the conversation, according to six White House officials and outside advisers who spoke on condition of anonymity because they were not authorized to publicly discuss private deliberations.

Those officials and advisers acknowledged that the victory lap was deliberately premature.

Trump's inner circle knows there will likely be further releases of embarrassing or politically damaging information.

Two years of Mueller: How sprawling Trump-Russia probe unfolded in ultimate D.C soap opera Here is a timeline of significant developments in Special Counsel Robert Mueller's investigation into Russia's role in the 2016 U.S. presidential election and whether President Donald Trump's campaign conspired with Moscow. 2017 May 9: President Trump fires FBI Director James Comey and days later Trump attributed the dismissal to 'this Russia thing.' May 17 - U.S. Deputy Attorney General Rod Rosenstein appoints former FBI Director Mueller as a special counsel to investigate Russian meddling in the 2016 election and to look into any links and/or coordination between the Russian government and people associated with Republican Trump's campaign. June 15 - Mueller is investigating Trump for possible obstruction of justice, the Washington Post reports. October 30 - Veteran Republican political operative and former Trump campaign chairman Paul Manafort, who worked for the campaign for five pivotal months in 2016, is indicted on charges of conspiracy against the United States and money laundering as is his business partner Rick Gates, who also worked for Trump's campaign. - Former Trump campaign adviser George Papadopoulos pleads guilty to a charge of lying to the FBI about his contacts with Russian officials. December 1 - Michael Flynn, Trump's national security adviser for less than a month who also had a prominent campaign role, pleads guilty to the charge of lying to the FBI about his discussions in 2016 with the Russian ambassador to Washington. 2018 February 16 - Federal grand jury indicts 13 Russians and three firms, including a Russian government propaganda arm called the Internet Research Agency, accusing them of tampering to support Trump and disparage Democratic candidate Hillary Clinton. The accused 'had a strategic goal to sow discord in the U.S. political system, including the 2016 U.S. presidential election' according to the court document filed by Mueller. - An American, Richard Pinedo, pleads guilty to identity fraud for selling bank account numbers after being accused by prosecutors of helping Russians launder money, buy Facebook ads and pay for campaign rally supplies. Pinedo was not associated with the Trump campaign. February 22 - Manafort and Gates are charged with financial crimes, including bank fraud, in Virginia. February 23 - Gates pleads guilty to conspiracy against the United States and lying to investigators. He agrees to cooperate and testify against Manafort at trial. April 3 - Alex van der Zwaan, the Dutch son-in-law of one of Russia's richest men, is sentenced to 30 days in prison and fined $20,000 for lying to Mueller's investigators, becoming the first person sentenced in the probe. April 9 - FBI agents raid home, hotel room and office of Trump's personal lawyer and self-described 'fixer' Michael Cohen. April 12 - Rosenstein tells Trump that he is not a target in Mueller's probe. April 19 - Former New York Mayor Rudy Giuliani, a Trump supporter in the election campaign, joins Trump's personal legal team. June 8 - Mueller charges a Russian-Ukrainian man, Konstantin Kilimnik, a Manafort business partner whom prosecutors say had ties to Russian intelligence, with witness tampering. July 13 - Federal grand jury indicts 12 Russian military intelligence officers on charges of hacking Democratic Party computer networks in 2016 and staged releases of documents. Russia, which denies interfering in the election, says there is no evidence that the 12 are linked to spying or hacking. July 16 - In Helsinki after the first summit between Trump and Russian President Vladimir Putin, Trump publicly contradicts U.S. intelligence agencies that concluded Moscow had interfered in the 2016 election with a campaign of hacking and propaganda. Trump touts Putin's 'extremely strong and powerful' denial of meddling. He calls the Mueller inquiry a 'rigged witch hunt' on Twitter. August 21 - A trial jury in Virginia finds Manafort guilty of five counts of tax fraud, two counts of bank fraud and one count of failure to disclose a foreign bank account. - Cohen, in a case brought by U.S. prosecutors in New York, pleads guilty to tax fraud and campaign finance law violations. Cohen is subsequently interviewed by Mueller's team. August 31 - Samuel Patten, an American business partner of Kilimnik, pleads guilty to unregistered lobbying for pro-Kremlin political party in Ukraine. September 14 - Manafort pleads guilty to two conspiracy counts and signs a cooperation agreement with Mueller's prosecutors. November 6 – Democrats gain control of the House in the elections, positioning the party to control panels with oversight authority of the Justice Department. November 8 - U.S. Attorney General Jeff Sessions resigns at Trump's request. He had recused himself from overseeing the Mueller inquiry because of his contacts with the Russian ambassador as a Trump campaign official. Trump appoints Sessions' chief of staff Matthew Whitaker, a critic of the Mueller probe, as acting attorney general. November 20 - Giuliani says Trump submitted written answers to questions from Mueller, as the president avoids a face-to-face interview with the special counsel. November 27-28 - Prosecutors say Manafort breached his plea deal by lying to investigators, which Manafort denies. Trump says he has not ruled out granting Manafort a presidential pardon. November 28 - Giuliani says Trump told investigators he was not aware ahead of time of a meeting in Trump Tower in New York between several campaign officials and Russians in June 2016. November 29 - Cohen pleads guilty in the Mueller investigation to lying to Congress about the length of discussions in 2016 on plans to build a Trump Tower in Moscow. 'I made these misstatements to be consistent with individual 1's political messaging and out of loyalty to individual 1,' says Cohen, who previously identified 'individual 1' as Trump. - The president criticizes Cohen as a liar and 'weak person.' December 12 - Two developments highlight growing political and legal risks for Trump: Cohen sentenced to three years in prison for crimes including orchestrating hush payments to women in violation of campaign laws before the election; American Media Inc, publisher of National Enquirer tabloid, strikes deal to avoid charges over its role in one of two hush payments. Publisher admits payment was aimed at influencing the 2016 election, contradicting Trump's statements. December 16 – President Trump tweets that Michael Cohen 'became a "Rat"' – using lingo associated with the mob for those who testify against higher-ups 2019 January 25 - Longtime Trump associate and self-proclaimed political 'dirty trickster' Roger Stone charged and arrested at his home in Florida. Stone is accused of lying to Congress about statements suggesting he may have had advance knowledge of plans by Wikileaks to release Democratic Party campaign emails that U.S. officials say were stolen by Russia. February 21 - U.S. judge tightens gag order on Stone, whose Instagram account posted a photo of the judge and the image of crosshairs next to it. February 22 - Manhattan district attorney's office is pursuing New York state criminal charges against Manafort whether or not he receives a pardon from Trump on federal crimes, a person familiar with the matter says. Trump cannot issue pardons for state convictions. February 24 - Senior Democratic U.S. Representative Adam Schiff says Democrats will subpoena Mueller's final report on his investigation if it is not given to Congress by the Justice Department, and will sue the Trump administration and call on Mueller to testify to Congress if necessary. February 27 - Cohen tells U.S. House Oversight Committee Trump is a 'racist,' a 'con man' and a 'cheat' who knew in advance about a release of emails by WikiLeaks in 2016 aimed at hurting rival Clinton. Trump directed negotiations for a real estate project in Moscow during the campaign even as he publicly said he had no business interests in Russia, Cohen testifies. Cohen also testifies that he 'never asked for, nor would I accept' a pardon from Trump, forcing his lawyer to issue a clarifying statement that Cohen 'could have been clearer' and standing by statement Cohen didn't 'personally' ask for a pardon. March 7 - Manafort is sentenced in the Virginia case to almost four years in prison. The judge also ordered Manafort to pay a fine of $50,000 and restitution of just over $24 million. March 13 - Manafort is sentenced to about 3-1/2 more years in prison in the Washington case, bringing his total prison sentence in the two special counsel cases to 7-1/2 years. - On the same day, the Manhattan district attorney announces a separate indictment charging Manafort with residential mortgage fraud and other New York state crimes, which unlike the federal charges cannot be erased by a presidential pardon. March 22 - Mueller submits his confidential report on the findings of his investigation to U.S. Attorney General William Barr. March 24 - Barr releases a summary of Mueller's report, saying the investigation did not find evidence that Trump or his associates broke the law during the campaign. White House spokeswoman Sarah Sanders says the summary is a complete exoneration of Trump. March 29 – After facing a backlash from Democratic critics, Barr tells Congress the report is nearly 400 pages long and that he will make a the report public, stating: 'Everyone will soon be able to read it on their own.' He writes that he is working on redactions including of material that could harm 'reputational interests of peripheral third parties.' April 3 – Democratic-run House Judiciary Committee votes to subpoena the full Mueller report. April 9 – Barr tells Congress he is reviewing FBI conduct that began the Mueller probe. April 11 – WikiLeaks founder Julian Assange is arrested in Britain on charges of conspiracy to hack U.S. government computers in 2010. The initial charge does not mention Russian interference in the 2016 U.S. elections. April 18 – Attorney General William Barr makes public a redacted version of the Mueller report, according to the Justice Department. Advertisement

Barr's letter, for instance, hinted that there would be at least one unknown action by the president that Mueller examined as a possible act of obstruction.

A number of White House aides have privately said they are eager for Russia stories, good or bad, to fade from the headlines.

And there is fear among some presidential confidants that the rush to spike the football could backfire if bombshell new information emerged.

'I think they did what they had to do. Regardless of what Barr reported, they needed to claim vindication,' said Republican strategist Alex Conant, who worked on Sen. Marco Rubio's 2016 presidential campaign.

'First impressions are important. And the first impression of the Mueller report was very good for Trump.'