Attorney General William Barr said Thursday he had no problem with special counsel Robert S. Mueller III testifying before Congress about his investigation into Russian meddling in the 2016 election or possible collusion with the Trump campaign.

“I have no objection to Bob Mueller personally testifying,” the attorney said at a news conference before the release of Mueller’s 400-page report.

Earlier Thursday, Democratic leaders called on Mueller to testify before Congress, hours before his redacted report will be seen for the first time by lawmakers and the public. (Barr released a four-page summary of the report’s key conclusions in March.)

Watch: Barr on Mueller report ahead of release — ‘No collusion’

Speaker Nancy Pelosi and Senate Minority Leader Charles E. Schumer said in a joint statement that Barr’s handling of the report has caused a “crisis of confidence.” Restoring the public’s trust in the integrity of the probe into possible connections between Russia and President Donald Trump’s campaign requires testimony by Mueller as soon as possible, they said.

“Attorney General Barr’s regrettably partisan handling of the Mueller report, including his slanted March 24th summary letter, his irresponsible testimony before Congress last week, and his indefensible plan to spin the report in a press conference later this morning — hours before he allows the public or Congress to see it — have resulted in a crisis of confidence in his independence and impartiality,” the statement reads.

Barr on Mueller memo: ‘The letter speaks for itself’

“We believe the only way to begin restoring public trust in the handling of the Special Counsel’s investigation is for Special Counsel Mueller himself to provide public testimony in the House and Senate as soon as possible. The American people deserve to hear the truth,” Pelosi and Schumer said. 

Trump continued his assault on the Mueller investigation Thursday morning, calling it “PRESIDENTIAL HARASSMENT!”

The Greatest Political Hoax of all time! Crimes were committed by Crooked, Dirty Cops and DNC/The Democrats.

— Donald J. Trump (@realDonaldTrump) April 18, 2019

PRESIDENTIAL HARASSMENT!

— Donald J. Trump (@realDonaldTrump) April 18, 2019

We cannot take Attorney General Barr’s word for it. We must read the full Mueller report, and the underlying evidence. This is about transparency and ensuring accountability. https://t.co/eNDgQKJHa8

— (((Rep. Nadler))) (@RepJerryNadler) April 18, 2019

House Judiciary Chairman Jerrold Nadler said he sent a letter to Mueller on Thursday asking him to appear before the panel “as soon as possible” and no later than May 23.

“We cannot take Attorney General Barr’s word for it,” the New York Democrat tweeted Thursday, referring to the Barr’s assessment of the Mueller report. “We must read the full Mueller report, and the underlying evidence. This is about transparency and ensuring accountability.”

House Intelligence Committee Chairman Adam B. Schiff also said Thursday he had invited Mueller to testify before his panel on its counterintelligence investigation.

House committee leaders on Wednesday called Barr’s news conference “inappropriate” and said it seemed designed to shape public perceptions of the investigation before the report is released. They called on Barr to cancel it.

The committee leaders — Nadler, Schiff, Oversight and Reform Chairman Elijah E. Cummings, Financial Services Chairwoman Maxine Waters and Foreign Affairs Chairman Eliot L. Engel — also raised concerns about news reports that the Department of Justice briefed the White House counsel on what to expect in the report as it prepared its rebuttal.

“These new actions by the Attorney General reinforce our concern that he is acting to protect President Trump,” they said.

Nadler called the reports “deeply troubling.”

I’m deeply troubled by reports that the WH is being briefed on the Mueller report AHEAD of its release. Now, DOJ is informing us we will not receive the report until around 11/12 tomorrow afternoon — AFTER Barr’s press conference. This is wrong. #ReleaseTheReport https://t.co/bR50HhGJ0i

— (((Rep. Nadler))) (@RepJerryNadler) April 17, 2019

Over the scope of the investigation, Mueller’s team issued convictions or indictments against Trump’s former national security adviser, Michael Flynn, former campaign chairman, Paul Manafort, and former personal lawyer, Michael Cohen.

But Republicans took a victory lap when Barr released his summary of the investigation in March without any new indictments handed down. Democrats have in the intervening weeks cast doubt on the credibility and completeness of Barr’s summary. 

Trump has repeatedly since the release of Barr’s memo said that it proves there was no collusion between his campaign and the Russians and that no one from his campaign or his White House had tried to obstruct Mueller’s investigation.

Barr testified before House and Senate subcommittees last week.