In a twist to the Mueller report saga, the U.S. Attorney General William Barr refused to testify before the Democrats-led House Judiciary Committee on Thursday.

On Wednesday, Barr had testified before the Senate Judiciary Committee relating to his handling of the Mueller report.

Barr’s decision to skip the Thursday meeting follows a procedural-row that erupted between House Democrats and the top law officer whether Barr should be allowed a public grilling by the committee’s staff attorneys.

Unprecedented procedures of House committee

The reason behind Barr’s plan to abstain was evident in a statement issued by a spokeswoman of the Department of Justice.

It said the conditions that House Judiciary Committee Chairman Jerrold Nadler placed on the committee are “unprecedented and unnecessary.” It also dubbed Nadler’s demand that the staff question Barr as “inappropriate.”

The Democratic-controlled committee has already issued a subpoena to the Justice Department to produce an “un-redacted version” of Mueller’s report and the underlying evidence.

In a statement, Nadler also confirmed that Barr will not appear before the House Committee but defended the panel’s decision on public questioning of Barr.

“Given his lack of candor in describing the work of the special counsel, our members were right to insist that staff council is permitted to question the attorney general,” Nadler said.

However, the committee’s meeting will take place Thursday, as scheduled, without Barr. Nadler said the intent was to get a full report and Mueller's underlying evidence, and the focus is not on Barr's testimony.

Justice Department says subpoena is not valid

Meanwhile, the Justice Department missed the Wednesday deadline to produce the full report authored by Robert Mueller to Nadler.  

However, the Justice Department informed Nadler that it cannot comply with its subpoena for the full, unredacted report by special counsel Robert Mueller.

In a letter to Nadler, Assistant Attorney General Stephen Boyd said the full report and underlying evidence cannot be submitted.

“This subpoena is not legitimate oversight,” Boyd wrote, and added that the request was “extraordinarily burdensome.”

Nadler warned that the Justice Department’s refusal to hand over the full report would invite contempt citation against Barr.

Barr aided Trump in claiming exoneration

Mueller, in a letter to Barr, took exception to the summary of the report that he made and said, “it did not fully capture the context, nature, and substance” of the full report.

Democrats allege that it was Barr’s summary that helped Trump to claim publicly that the Mueller report had exonerated him, long before the world had seen the full report.

“No Collusion, No Obstruction, Complete and Total Exoneration. Keep America Great!” Trump tweeted on March 25.

In his testimony to the Senate Judiciary Committee on Wednesday Barr defended his handling of the Mueller report even as criticism from Democrats turned shrill and calls became louder for his resignation.