Several candidates decried the summary from President DonaldTrump's "handpicked" Attorney General, whose summary of Mueller's report stated that the "Special Counsel did not find that the Trump campaign, or anyone associated with it, conspired or coordinated with the Russian government in these efforts," saying the four-page letter does not provide the public with sufficient information about Mueller's findings.
"Let's speak truth that the American public deserves transparency and accountability and the Mueller report must be made public for a full accounting of what happened," California Sen. Kamala Harris, a member of the Senate Judiciary Committee, said during a campaign rally in Atlanta Sunday evening. "The Attorney General of the United States must be required to come and testify before Congress instead of just submitting a four page memo of what happened.”
"A short letter from Trump's hand-picked Attorney General is not sufficient," Harris added in a Sunday evening tweet.
Barr, who was selected by Trump to replace his first attorney general, former Alabama Sen. Jeff Sessions, was confirmed by the U.S. Senate by a vote of 54-45 last month. All six Democratic U.S. Senators who have announced presidential bids voted against Barr's confirmation.
"This is simply a four-page letter from the president’s attorney general that summarizes what happened and leaves open a lot of questions," Minnesota Sen. Amy Klobuchar, who, like Harris, sits on the Senate Judiciary, said in an interview with CBS News on Monday. "Barr, during his [confirmation] hearing and now as attorney general has pledged that he wants to make everything he can public and we’re going to call him on that. We want to see this report."
"The American people deserve the opportunity to read the full Mueller report, not a sanitized summary from Donald Trump’s hand-picked AG," Washington Gov. Jay Inslee tweeted Sunday evening. "The Trump administration has proven it can’t be trusted. It’s time to #releasethereport."
"Trump's attorney general just release his four-page summary of the Mueller report. That's not good enough. The American people deserve to see the full report and findings from this investigation immediately -- not just the Trump administration's in-house summary," read an e-mail blast from New Jersey Sen. Cory Booker's presidential campaign.
Former Georgia gubernatorial candidate Stacey Abrams likened Barr's summary to "your brother summarize your report card to your parents."
"It is deeply inappropriate for someone who is an avowed partisan, who, in part auditioned for the job by disparaging the report to be responsible for summarizing the report." Abrams said in an interview Sunday. "I am always suspect of a process that does not have independence and transparency, and I think we should demand that we get to see the report in full, no redactions and no questions.”
The attention on Barr is only expected to grow in the coming days, as Democratic leaders like House Judiciary Chairman Jerrold Nadler have already said they will ask the attorney general to testify publicly before Congress.
On Twitter, President Trump was quick to claim "total EXONERATION," after Barr's summary was released, despite the fact that the Special Counsel specifically declined to exonerate him on the issue of whether or not he obstructed justice.
Asked Monday by ABC News' Chief White House Correspondent Jonathan Karl in the Oval Office whether or not Mueller's investigation was a "witch hunt," President Trump said he said the investigation went on "far too long," but added that he would not mind if Mueller's full report was made public.
"Up to the Attorney General but it wouldn't both me at all," Trump said.
But even amid their unified calls for Barr to release the full Mueller report, some Democratic candidates will now have to contend with their claims that went beyond just speculation over Trump and his 2016 campaign's ties to Russia.
"You have a president, who in my opinion, beyond a shadow of a doubt, sought to, however ham-handedly, collude with the Russian government, a foreign power, to undermine and influence our elections," former Texas Rep. Beto O'Rourke, who launched his presidential campaign earlier this month, said on the campaign trail in South Carolina on Saturday.
While other candidates have not gone as far as O'Rourke, their rhetoric has suggested they believe that foreign powers do hold sway over Trump and his administration.
"Under this administration, America's position in the world has never been weaker. When democratic values are under attack around the globe, when authoritarianism is on the March, when nuclear proliferation is on the rise, when we have foreign powers infecting the White House like malware,” Harris, who told ABC's Jimmy Kimmel last week that Americans want a candidate who can "prosecute the case" against Trump in 2020, said in January during her official campaign kickoff speech in Oakland, California.
Other Democratic presidential hopefuls like South Bend, Indiana Mayor Pete Buttigieg, say the release of Barr's summary underscores the point that the party can never fully rely on the famed prosecutor's mysterious report as the sole rationale for denying Trump a second term in office.
"I think this is further evidence that it would be a mistake for Democrats to think that the way for the Trump presidency to end is by way of investigation," Buttigieg, who is expected to formally announce his presidential candidacy next month, said in an interview with MSNBC on Sunday. "That could, of course, happen but we’ve got to be paying attention to the kinds of conditions that made it possible for somebody like him to get here in the first place."
ABC News' Kendall Karson contributed to this report.