Washington (CNN) House Judiciary Chairman Jerry Nadler subpoenaed Attorney General William Barr on Friday for a full, unredacted version of special counsel Robert Mueller's report and the underlying evidence by May 1, teeing up a showdown with the Justice Department that's likely to end up in court.

"My Committee needs and is entitled to the full version of the report and the underlying evidence consistent with past practice. The redactions appear to be significant," wrote Nadler in a statement. "We have so far seen none of the actual evidence that the Special Counsel developed to make this case."

"Even the redacted version of the report outlines serious instances of wrongdoing by President Trump and some of his closest associates," he said. "It now falls to Congress to determine the full scope of that alleged misconduct and to decide what steps we must take going forward."

CNN has reached out to the Justice Department for comment.

House Democrats, already seething over Barr's handling of Mueller's report, are swiftly moving to try to see what else Mueller included in the roughly 36 pages' worth of redactions in the report.

Barr released the special counsel's two-volume report on Thursday with four types of redactions: grand jury material, information about ongoing investigations, classified material and to protect the privacy of peripheral third parties. The Justice Department plans to show a select group of lawmakers all of the redactions except for grand jury material, which Barr has argued legal statutes do not allow him to release to Congress.

But that's not good enough for Democrats in Congress, who say they are entitled to view grand jury material as part of their oversight duties. The swiftness with which Nadler issued the subpoena -- less than 24 hours after the redacted report was released -- signals that House Democrats don't believe they have a negotiating partner in Barr.

Democratic congressional leaders also rejected the Justice Department proposal for congressional and committee leaders to view a less-redacted version of the report, telling Barr in a letter Friday that the plan was unacceptable.

"Given the comprehensive factual findings presented by the special counsel's Report, some of which will only be fully understood with access to the redacted material, we cannot agree to the conditions you are placing on our access to the full report," the lawmakers wrote in the letter.

Department spokesperson Kerri Kupec called Nadler's subpoena unnecessary and promised to keep working with lawmakers.

"In the interest of transparency, the Attorney General released the Special Counsel's 'confidential report' with only minimal redactions," Kupec said in a statement. "The Department of Justice has also made arrangements for Chairman Nadler and other Congressional leaders to review the report with even fewer redactions. In light of this, Congressman Nadler's subpoena is premature and unnecessary. The Department will continue to work with Congress to accommodate its legitimate requests consistent with the law and long-recognized executive branch interests."

Democrats slammed the attorney general on Thursday for issuing a summary of Mueller's conclusions they say mischaracterized what the Mueller report found on both collusion and obstruction of justice. Barr's decision to hold a press conference before sending the report to Congress solidified Democrats' view that Barr was out to protect the President.

Republicans accuse Democrats of asking the attorney general to break the law by requesting grand jury material, arguing that Congress is not entitled to that information unless a formal impeachment proceeding has been opened -- something Democratic leaders have resisted thus far.

"Today's subpoena is wildly overbroad. It commands the department to provide Congress with millions of records that would be plainly against the law to share because the vast majority of these documents came as a result of nearly 2,800 subpoenas from a grand jury that is still ongoing," said Georgia Rep. Doug Collins, the top Republican on the House Judiciary Committee.

Since the report was released Thursday, Nadler and other Democrats have pointed to the portion of Mueller's report that laid out a case for Congress' power to investigate obstruction of justice.

When asked if the Mueller report would provide a "road map" should Democrats open impeachment proceedings, Nadler told reporters on Thursday that it was "too early" to discuss that. But Nadler added the special counsel "probably" wrote the report with that "intent." Barr's redactions, he said, seemed to "frustrate that intent."

"We will have to go follow the evidence where it leads and I don't know exactly where it will lead," Nadler said Thursday.

The Mueller report is the result of a nearly two-year investigation into how Russia interfered in the 2016 presidential election to help the Trump campaign and whether the President then obstructed that probe.