(CNN) House Democrats are demanding that Attorney General William Barr release special counsel Robert Mueller's report to the public, a potential preview of the looming battle over Mueller's confidential report.

Six Democratic committee chairs, led by Judiciary Chairman Jerry Nadler, sent a letter to Barr on Friday arguing that the public should be given a chance to view Mueller's report "without delay and to the maximum extent permitted by law."

"After nearly two years of investigation — accompanied by two years of direct attacks on the integrity of the investigation by the President — the public is entitled to know what the Special Counsel has found," the lawmakers wrote.

When Mueller's investigation is completed, he is required to submit a confidential report to the attorney general, detailing the decisions that were made to prosecute or not prosecute those who were investigated. Justice Department officials are preparing for Mueller's report soon, although a Justice Department official said Friday that Mueller's report is not expected next week.

Once Mueller submits his report, it's up to Barr to decide what to provide to Congress and to the public.

At his confirmation hearing, Barr said he wanted to be as transparent as he could with Mueller's report, but left himself wiggle room by saying he would have to follow Justice Department regulations.

Democrats are unlikely to be satisfied with a summary from Barr detailing Mueller's findings. Several key Democrats have already signaled they could subpoena the Justice Department to obtain Mueller's report or the underlying evidence that he gathered, though Friday's letter does not mention the prospect of a subpoena or court fight.

"A summary written by Attorney General Barr in place of the Mueller report will not be acceptable," said California Sen. Dianne Feinstein, the top Democrat on the Senate Judiciary Committee, in a statement Friday. "This isn't limited to a question of whether crimes have been committed. Congress must also determine if there was misconduct or abuse of power."

While Democrats are likely to go to court to fight for access to Mueller's report if necessary, Republicans in Congress have also expressed a desire for the report to be made public. Polling shows the public overwhelmingly feels the same way, too.

In their letter, the House Democratic leaders sought to push back on the notion that the Justice Department shouldn't share derogatory information about people it doesn't charge -- at least when it comes to President Donald Trump.

"Although we recognize the policy of the Department to remain sensitive to the privacy and reputation interests of individuals who will not face criminal charges, we feel that it is necessary to address the particular danger of withholding evidence of misconduct by President Trump from the relevant committees," the lawmakers wrote.

"To maintain that a sitting president cannot be indicted, and then to withhold evidence of wrongdoing from Congress because the President will not be charged, is to convert Department policy into the means for a cover-up," they said.

Democrats have also pointed to the Republican-led investigations in the last Congress into the FBI's handling of the Hillary Clinton email investigation and the start of the Russia investigation as a precedent for Barr to provide additional information to Congress.

Republicans fought the Justice Department and the FBI for months to view sensitive materials, particularly surrounding the foreign surveillance warrant for former Trump campaign adviser Carter Page.

"In other closed and pending high-profile cases alleging wrongdoing by public officials, both the Department and the FBI have produced substantial amounts of investigative material, including classified and law enforcement sensitive information, to the House of Representatives," the Democrats wrote.