John Dean on Sunday suggested Attorney General William Barr could be hiding something "fairly ugly" from special counsel Robert Mueller's report.

"He put a little lipstick on something that might've been fairly ugly," Dean, who served as President Richard Nixon's White House counsel, told CNN.

There's no evidence Barr is hiding anything, but he's under pressure from Democrats to make the report available to the public after releasing a summary on Sunday

John Dean, who was President Richard Nixon's White House counsel amid the Watergate scandal, on Sunday suggested Attorney General William Barr could be hiding something "fairly ugly" from special counsel Robert Mueller's report on the Russia investigation.

"He put a little lipstick on something that might've been fairly ugly," Dean told CNN of Barr and his summary on Mueller's report. "We haven't really seen the underlying report, but I have some suspicions that the reason he boiled this down the way he did is because it's not very attractive. [Mueller's] words are very different than Barr's, I suspect.”

Dean also said, "I think [Barr] had a heads up on this. I think one of the reasons he backed off on the obstruction issue is there was a fundamental disagreement with the department as to whether a sitting president was capable of obstructing justice."

"Those issues will be sorted out as this report slowly, hopefully, surfaces," Dean added.

According to Barr's summary, Mueller's report said he did not find evidence that Trump or any of his associates colluded with the Kremlin in its interference into the 2016 presidential election.

The attorney general also said, "The Special Counsel states that 'while this report does not conclude that the President committed [an obstruction-of-justice] crime, it also does not exonerate him.'" Additionally, Barr said that he and Deputy Attorney General Rod Rosenstein concluded there were not substantial grounds to move forward with obstruction of justice charges against the president.

Read more: Barr's summary of the Mueller report is out. Here are the key Trump-Russia questions we still don't have answers to.

It's unclear how much of Mueller's report will be made public moving forward.

Barr has a broad view of executive authority and prior to being nominated and ultimately confirmed as Trump's attorney general wrote a memo to the Justice Department criticizing Mueller's inquiry into the president and obstruction of justice as "fatally misconceived."

Alluding to this in a tweet on Sunday night, Dean said, "Having re-read William Barr's June 2018 Memo critiquing Mueller’s obstruction investigation and now his summary of Mueller’s Report, it is clear that Richard Nixon would not have been forced to resign his office if Barr had been Attorney General. Barr wants a POTUS above the law."

With that said, there's currently no direct evidence Barr, who's had a long legal career in Washington, is hiding any particularly damning or pertinent information from the public.