Update4: Attorney General William Barr says that he is reviewing the "conduct" of the FBI during its original 2016 Trump-Russia investigation, following calls by GOP legislators to investigate the origins of the probe.

Barr confirms that he is "reviewing the conduct of the [Russia] investigation," and indicates he still takes Devin Nunes seriously pic.twitter.com/2L7Tk19ZqN — Aaron Rupar (@atrupar) April 9, 2019

After explaining that DOJ Inspector General Michael Horowitz has a pending investigation into FISA abuse, Barr said "I am reviewing the conduct of the Russia investigation, and all the aspects of the counterintelligence investigation that was conducted in the summer of 2016."

Barr: "I am reviewing the conduct of the Russia investigation, and all the aspects of the counterintelligence investigation that was conducted in the summer of 2016.” — Shirtless Pundit 🇺🇸 (@zachhaller) April 9, 2019

The comments come after House Intelligence Committee Ranking Member Devin Nunes, R-Calif., said over the weekend he was preparing to send eight criminal referrals to the Justice Department this week regarding alleged misconduct by DOJ and FBI officials during the Trump-Russia investigation. It is unclear whom Nunes will refer for investigation, and what the process at the Justice Department might be. -Fox News

Barr says he hasn't seen Nunes' referrals yet, adding "Obviously, if there is a predicate for investigation, it will be conducted."

Update3: Barr says that the Justice Department's Inspector General is working on reviewing the process used by the FBI to obtain a FISA surveillance warrant on Trump campaign aide Carter Page, and that the IG report will be complete in May or June. Barr also said that he's overseeing a separate wider investigation.

Barr says the DOJ IG is working on a review of FISA process as it relates to Trump/Russia investigation (phony Dossier was cited to obtain warrant on Carter Page.) Says review will be complete in May or June. Barr also overseeing a separate, wider review. Reckoning coming soon. — Michael Tracey (@mtracey) April 9, 2019

He also said he will testify before the Judiciary Committees about all aspects of the Mueller report upon its release, including working with Rep. Nadler to explain the redactions.

Barr affirms his willingness to testify before the Judiciary Committees about all aspects of the Report once it is released. Also says he will work with Rep. Nadler to provide further information about redacted portions. Zero indication of any coverup or second-order conspiracy. — Michael Tracey (@mtracey) April 9, 2019

Update2: Barr says that the redacted Mueller report will be ready for release in one week, and that he is relying on discretion in deciding what to make public.

Update: Watch live:

Attorney General Bill Barr has arrived for his appearance before a House Appropriations panel to testify on the DOJ budget. We expect some members to ask about the Mueller probe and report. Stay tuned! pic.twitter.com/hhGBsQGuXY — Morgan Chalfant (@mchalfant16) April 9, 2019

***

Attorney General William Barr will appear before the House of Representatives appropriations subcommittee on Tuesday for the first time since special counsel Robert Mueller submitted his Russia report surrounding the 2016 US election, reports Reuters.

While the session is intended to explore the Trump administration's $29 billion Justice Department fiscal 2020 budget request, Barr will undoubtedly face questions about the Mueller report and when Congress might expect to see a redacted version.

Barr has been working with Mueller to redact sensitive portions of the report, including grand-jury information following a ruling last week at the US Court of Appeals for the DC Circuit. He has indicated that it will be ready by mid-April, in just a few days.

Mueller turned his confidential report over to Barr on March 22 following a 22-month-long probe into whether Donald Trump may have colluded with Russia during his 2016 presidential campaign and whether Trump later obstructed inquiries into the matter. On March 24, Barr released a four-page letter to Congress laying out what he said were Mueller’s main findings. Barr is expected to submit a redacted copy of the full report to the public and Congress by mid-April, or even sooner. -Reuters

Democrats are using the redactions to suggest that Barr and the Trump administration are holding back vital information which they hope might deliver the impeachment they've sought for more than two years, despite Mueller's findings of no collusion - and AG Barr and Deputy AG Rod Rosenstein determining that Trump did not obstruct the probe.

On Monday, Rep. Doug Collins - the top Republican on the Democrat-controlled House Judiciary Committee, wrote a scathing letter to the panel's chairman, Rep. Jerry Nadler (D-NY) accusing him of putting Attorney General William Barr in an "untenable but politically convenient situation." Barr would be forced to "break the law" if he provides an unredacted report - and he doesn't, Nadler will "label him as part of a cover-up."

According to Barr's written testimony, the Attorney General will focus Tuesday's discussion on issues including immigration enforcement, the opioid epidemic and combating violent crime.

He is scheduled for a Wednesday appearance in front of a Senate appropriations panel.