The contempt resolution against Barr now moves to the full House.

If it is approved, it would trigger a criminal referral to the US attorney for the District of Columbia, which would decide whether to prosecute.

Nadler said the panel had to act because Trump's stonewalling is creating a "constitutional crisis."

The House Judiciary Committee voted along party lines to hold Barr in contempt for refusing to turn over the full, unredacted Mueller report.

Democrats have been trying to review Mueller's material - and determine whether they should impeach the president - by examining the evidence the special counsel gathered over his two-year-long investigation.

But the Justice Department has refused to relinquish that information, despite a congressional subpoena. The Trump Administration cited legal reasons for declining the request and has questioned whether Democrats' motives constitute "legitimate oversight."

"As we have repeatedly explained, the attorney-general could not comply with your subpoena in its current form without violating the law, court rules, and court orders, and without threatening the independence of the Department of Justice's prosecutorial functions," Assistant Attorney-General Stephen Boyd wrote in a letter to Congress, formally asserting executive privilege.

The White House's use of the rare presidential secrecy prerogative stood in stark contrast to Trump and his allies' frequent boast of "total exoneration" for the president from the Mueller report.

Democrats have argued that if Trump really had nothing to hide, he and Barr wouldn't be blocking so many of their investigations - including Mueller's complete findings.

The White House assertion of privilege represents the latest collision between Trump and House Democrats, who have seen their investigations of the president blocked at every turn.

Some legal experts argued the White House and Attorney-General were simply stalling, making a dubious claim of privilege over the Mueller report they have intensively reviewed to put off a fight in court.

Democrats assailed Trump officials and accused the White House of trying to hide the truth from the public.

"This decision represents a clear escalation in the Trump administration's blanket defiance of Congress's constitutionally mandated duties," Nadler said, later adding:

"As a coequal branch of government, we must have access to the materials that we need to fulfill our constitutional responsibilities in a manner consistent with past precedent."

The move against Barr represented just the second time in history that a sitting Attorney-General would be held in contempt of Congress; the Republican-led House admonished Attorney-General Eric Holder in 2012 over his failure to provide documents to Congress.

Barr released a redacted, 448-page version of the Mueller report on April 18 that found no conspiracy between the Trump campaign and Russia, which interfered in the 2016 election. The report also identified 10 instances of possible obstruction of justice by Trump.

Democrats moved to reprimand Barr for ignoring their congressional subpoena. And during the Wednesday contempt hearing, they cast the White House claim of privilege as bogus, arguing the administration waived privilege by allowing aides to testify before Mueller - and Barr to release the report to the public.

At the White House press secretary Sarah Sanders defended the decision in a Wednesday morning statement.

"The American people see through Chairman Nadler's desperate ploy to distract from the president's historically successful agenda and our booming economy. Neither the White House nor Attorney-General Barr will comply with Chairman Nadler's unlawful and reckless demands," Sanders said.

"Faced with Chairman Nadler's blatant abuse of power, and at the Attorney-General's request, the president has no other option than to make a protective assertion of executive privilege."

The assertion of privilege was broad - covering all of the underlying materials from Mueller's investigation, such as reports of interviews and notes of witnesses, as well as the entire, unredacted Mueller report.

The Justice Department considered it important for the White House to assert executive privilege before the House vote on contempt because, in their view, doing so would effectively invalidate the citation, a person familiar with the matter said.

The Justice Department believed that Barr could not be legitimately held in contempt for withholding materials over which the president had asserted executive privilege, the person said. Democrats, countered, that that was not the case and redoubled their efforts.

During the Judiciary session, Democrats and Republicans assailed each other, with the majority accusing the minority of trying to hide the fuller Mueller report from the public while the Republicans said Democrats were being overzealous in their probes.

"The Attorney-General of the United States refused to provide information that is not privilege and is subject to a subpoena," said Representative Ted Deutch.

"There is no privilege for this information. Executive privilege is not a cloak of secrecy that drapes across" Washington, he said.

Republicans used their time to defend Barr's name and tried to divert the conversation back to the origins of the Russia investigation, accusing the FBI of being guided by anti-Trump bias.

"Bill Barr is following the law and what's his response? Democrats are going to hold him contempt," said Representative Jim Jordan, R-Ohio, "I think it's all about trying to destroy Bill Barr because Democrats are nervous that he's going to get to the bottom of everything."

The GOP has stood steadfast with Trump since he took office, rarely breaking with the president, dismissing the multiple investigations and insisting it was time for Democrats to move on.

AP, Washington Post