Justice Department officials met Monday with Democratic staff for the House Judiciary Committee, but the two sides remained far apart on the terms for Attorney General William P. Barr’s scheduled testimony later this week about the report of special counsel Robert S. Mueller III.

Barr is set to testify Wednesday and Thursday before the Senate and House Judiciary committees about his handling of the conclusions reached by Mueller following his investigation into President Trump’s conduct and Russia’s election interference in 2016. The House hearing is suddenly in doubt over a dispute about who would question Barr.

The days-long standoff centers on Democrats’ demand that part of the questioning be conducted by the committee’s lawyers, according to people familiar with the discussions.

Justice Department officials have threatened that Barr may not appear for the hearing under such conditions, while House Democratic staffers have countered that the attorney general may be subpoenaed if he refuses.

It is standard practice in Congress for lawmakers to question witnesses directly, though decades ago, questioning by committee staff was more common.

Even if Barr ends up not testifying this week to House lawmakers, his Senate hearing Wednesday is expected to proceed.

Barr’s appearance was not the focus of Monday’s discussion between Justice Department officials and House committee staffers. The meeting was held to discuss whether lawmakers would be able to secure more access to redacted portions of the Mueller report before Wednesday, the date the committee set for the Justice Department to turn over its full contents to Congress.

Barr made the Mueller report public earlier this month, but with redactions to avoid revealing grand jury material and information that could compromise ongoing investigations. Democrats are demanding many lawmakers — not just a small number of senior party leaders — be allowed to view its redacted portions.

Rep. Jerrold Nadler (D-N.Y.), the House Judiciary Committee chairman, was adamant following the discussion that “there is no middle ground” in the panel’s standoff with Barr over the terms of his hearing.

“We’ve been very clear: Barr has to come. He has to testify. It’s none of the business of a witness to try to dictate to a congressional committee what our procedures for questioning him are,” Nadler said. “It’s not up to anybody from the executive branch to tell the legislative branch how to do our business.”

Nadler said the Justice Department seems “very afraid” of the committee counsel’s questions, adding that if Barr does not show, they would “take appropriate action.” Committee aides indicated Sunday that lawmakers could subpoena the attorney general’s testimony.

While Barr’s appearance remains uncertain, according to a committee aide, the Justice Department sent staff to the Rayburn House Office Building on Monday to assess the hearing room in which Barr’s testimony would take place, if it goes ahead.

Democrats have grown frustrated by what they see as stonewalling from the administration, and that irritation is fueling calls from rank-and-file members to start impeachment proceedings. At this point, leaders are acutely aware that public sentiment does not favor that approach.

But some members believe that, if the president keeps rebuffing congressional requests and summons for interviews and documents, public sentiment may shift, making impeachment more politically palatable.

Nadler was cautious when asked whether the case for impeachment proceedings could become stronger should Barr refuse to appear on Thursday or if the Justice Department misses lawmakers’ Wednesday deadline to turn over Mueller’s full report.

“It certainly builds a case that the administration and the president is engaged in wholesale obstruction of Congress. Completely extra-constitutional. Trying to make the presidency not responsive to Congress, trying to make the presidency into a monarchy. It’s absolutely unacceptable, and we’ll take whatever action we have to do to deal with it,” Nadler said.

But impeachment? “That remains to be seen,” he said.