Protesters rally outside the White House on Monday. (Jacquelyn Martin/AP)

Attorney General William P. Barr is expected to miss House Democrats’ deadline to provide Congress the full report documenting special counsel Robert S. Mueller III’s investigation into Russian interference in the 2016 election, increasing the likelihood lawmakers will subpoena the Justice Department.

Rep. Jerrold Nadler (D-N.Y.), the chairman of the House Judiciary Committee, said that during a Wednesday phone call with Barr, the attorney general said it would be “weeks, not months” before lawmakers can see the report, making it “apparent that the department will not meet the April 2 deadline that we set” earlier this week.

Barr would not promise that “an unredacted full report with the underlying documents, evidence, would be provided to Congress and to the American people,” Nadler said. “We’re not happy about that, to put it mildly.”

Though Nadler would not say whether lawmakers will issue a subpoena, he told reporters that April 2 was “a hard deadline that we set and we mean it.”

A Justice Department spokeswoman did not immediately respond to a request for comment.

Barr informed Congress on Sunday of Mueller’s main findings, writing in a four-page letter to the heads of the House and Senate Judiciary committees that the special counsel did not establish a criminal conspiracy between the Trump campaign and Russia to sway the election and offered no conclusion on whether the president sought to obstruct justice during the investigation.

The report is several hundred pages — but less than 1,000, Nadler said — and Democrats say it is vital to see its details before they can determine whether they agree with Barr’s assessment, believing there may evidence of collusion Mueller did not consider as part of his findings.

On the question of obstruction, Barr wrote in his summary for lawmakers that he and Deputy Attorney General Rod J. Rosenstein had decided the evidence was “not sufficient” to conclude Trump had “committed an obstruction-of-justice offense.” Nadler said he did not discuss with Barr why he made that determination, but Democrats have vowed to look further into the evidence.

Barr pledged he would make himself available for an interview with the Judiciary Committee, Nadler told reporters, which would happen “reasonably soon.” Barr is expected on Capitol Hill for a budget hearing with the House Appropriations Committee on April 9.

“We may very well want Mueller after Barr,” Nadler added.