The chairman of the House Judiciary Committee has given Attorney General William P. Barr one last shot to accommodate lawmakers seeking access to a more complete version of special counsel Robert S. Mueller III’s report before beginning contempt proceedings.

In a letter Friday, Rep. Jerrold Nadler (D-N.Y.) gave Barr until Monday to respond to his request that the Justice Department allow more lawmakers the chance to read the fuller report as well as turn over investigative material underlying the report. Barr had released a redacted version of the report on April 18.

Earlier this week, citing a “compelling need to protect the autonomy and effectiveness of its investigations,” the department said it was “unable to provide” Mueller’s investigative files in response to a committee subpoena.

“The committee is prepared to make every realistic effort to reach an accommodation with the department,” Nadler wrote. “But if the department persists in its baseless refusal to comply with a validly issued subpoena, the committee will move to contempt proceedings and seek further legal recourse.”

The Justice Department declined to comment on Nadler’s letter.

The letter is the latest salvo in a widening war between the White House and congressional Democrats, who are seeking to have Mueller and former White House counsel Donald McGahn testify. On Thursday, Barr snubbed Nadler’s committee, failing to show for a scheduled hearing after he disagreed with the panel’s format.

Attorney General William P. Barr testifies during a Senate Judiciary Committee hearing on Capitol Hill on Wednesday. (Andrew Harnik/AP)

In his report, Mueller did not find a conspiracy between the Trump campaign and Russian officials seeking to interfere in the 2016 presidential election. The special counsel identified 10 instances of possible obstruction of justice by Trump.

In a March 27 letter that surfaced this week, Mueller complained to Barr that his four-page memo summarizing the report “did not fully capture the context, nature, and substance” of the special counsel’s work.

Last month, the Justice Department offered to make a less-redacted version of the 448-page Mueller report available to select members of the House and Senate — the chairmen and ranking members of the two chambers’ Intelligence committees, the leaders and minority leaders of the House and Senate, and the chairmen and ranking members of each chamber’s judiciary panels. That’s a total of 12 lawmakers, with one staff member each.

Top Senate and House Democrats rejected the offer, saying it would not permit them to discuss the report with other lawmakers who have top security clearances and it would prevent them from carrying out an effective congressional investigation.

“In order for Congress to fulfill its functions as intended by the Constitution, it must operate as a coequal and coordinate branch of government,” House Speaker Nancy Pelosi (D-Calif.) and Senate Minority Leader Charles E. Schumer (D-N.Y.) said in a letter to Barr last month.

In his letter to Barr, Nadler said the Justice Department “has never explained why it is willing to allow only a small number of members to view a less-redacted version of the report, subject to the condition that they cannot discuss what they have seen with anyone else.”

In its April 18 offer made by Assistant Attorney General Stephen Boyd, the department suggested it was because of the “sensitive nature of the information.”

At the White House, press secretary Sarah Sanders scoffed at Nadler’s deadline, saying House Democrats “look ridiculous and silly.”

“Not a single Democrat has yet to go read the less-redacted version of the report,” Sanders said.

Democrats have declined to read the less-redacted version of the report in a secure room at the Capitol in protest of the arrangement offered by the Justice Department.

On Friday afternoon, Rep. Douglas A. Collins (Ga.), the top Republican on the Judiciary Committee, criticized Nadler for placing “absurd demands on the department to comply with his oversight request.” Echoing language in Mueller’s complaint to Barr, Collins said in a statement that Nadler’s accusations “do not fully capture the context, nature and substance” of the situation.

The House Judiciary Committee also wants the department to seek a court order to permit disclosure to Congress of grand jury material. The department has stated that revealing such material in response to congressional oversight requests is barred by law. But, Nadler says, courts have provided grand jury materials to Congress under the “judicial proceeding’’ exception in the past.

Finally, the committee Democrats want “a defined set” of investigative material, including witness interviews — known as “302s” — and contemporaneous notes taken by witnesses of relevant events. “Since these materials are publicly cited and described in the Mueller report, there can be no question about the committee’s need for and right to” the evidence to evaluate the facts Mueller established, Nadler wrote.

That need is amplified, he said, when department policy prohibits the indictment of a sitting president “and instead relies upon Congress to evaluate whether constitutional remedies are appropriate.”

Meanwhile, Nadler’s committee is working to secure Mueller’s testimony later this month. “We’re still firming things up, but we’re still on target” for an appearance by May 23, a committee aide said, speaking on the condition of anonymity to freely discuss private deliberations.

Talks are also ongoing with McGahn’s lawyer over his appearance. The committee Democrats have requested that he turn over by Tuesday documents that he submitted to the special counsel. Those records are in the possession of his lawyer.

Separately, Senate Judiciary Committee Chairman Lindsey O. Graham (R-S.C.) wrote to Mueller on Friday asking if he would like to provide testimony regarding Barr’s characterization of a phone call with the special counsel.

During a hearing on Wednesday, Barr testified that during the call Mueller did not challenge the accuracy of a four-page summary of key findings in Mueller’s report that was sent to Congress last month and was only concerned with media coverage of its release.

“Please inform the Committee if you would like to provide testimony regarding any misrepresentation by the Attorney General of the substance of that phone call,” Graham wrote.

Before the call, Mueller had written Barr a letter saying he was concerned that his summary “did not fully capture the context, nature and substance” of his report.

John Wagner contributed to this report.