"While this report does not conclude that the president committed a crime, it also does not exonerate him", Barr cited Mueller as saying.
Mr Trump faces continuing risk from other investigations, with federal prosecutors in NY looking into his company, presidential campaign and inaugural committee.
Kamarck was referring to House Speaker Nancy Pelosi, the top U.S. Democrat, who recently said in a Washington Post interview that the country should not go down the path of impeachment because Trump is "just not worth it".
Under Department of Justice regulations, Barr is empowered to decide how much to disclose of the Mueller report publicly. Their reason? They don't believe a word "Trump's hand-picked Attorney General" has to say.
Under long-standing Justice Department policy, USA presidents cannot be indicted while serving in office, but can face charges once they leave office.
"It is unconscionable that President Trump would try to spin the findings as if his conduct was acceptable", he added, after noting that according to Barr's summary, Mueller said his report did not "exonerate" the president on the accusations of obstruction of justice.
Dallas Faces Flood Risk from Trinity River This Spring
The Plains farm aid nonprofit Farm Rescue is launching an effort to bring donated hay to flood-stricken Nebraska ranchers. Triggered by a massive winter storm last week, numerous cities along the banks of the Missouri River have been inundated.
For their part, Democrats called for Mueller's full report to be released and vowed to press on with their own investigation, setting up future clashes with the White House.
That ambiguity has given otherwise chastened Democrats - many of whom told Americans over the past two years that Mr Mueller's report would result in the discovery of impeachable offences against Mr Trump - an opening.
Earlier this month he launched the Democrats' most ambitious investigation yet into alleged obstruction of justice and abuse of office by Trump, targeting 81 individuals and entities.
White House aides say Trump has not been briefed on the outcome of Mueller's investigation, a probe that has clouded nearly the entirety of his 26-month presidency.
The chairman of the House Judiciary Committee, which would determine whether to impeach the president, said Attorney General William P. Barr should testify before his panel.
"The investigation did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities".
Second Cyclone Bears Down on West Australia
Current predictions suggest the cyclone will move more than 400 kilometres inland before it weakens to a tropical storm. It is equivalent of a category three hurricane and expected to make a landfall on Sunday.
Barr's letter marked the conclusion of the disturbing investigation into allegations that Trump's election campaign coordinated and colluded with Russians to skew the 2016 vote so the billionaire real estate magnate would win.
The President tweeted: "No collusion, no obstruction, complete and total exoneration".
Mueller's investigation ensnared almost three dozen people, senior Trump campaign operatives among them.
He has frequently derided Mueller's work as a "witch hunt" and denies collaborating with Moscow or obstructing justice.
Barr's chief of staff called White House counsel Emmet Flood at 3 pm Sunday to brief him on the report to Congress.
The Mueller report did not find that the Trump campaign or its associates "conspired or coordinated" with Russian Federation, but it stopped short of exonerating the US president of obstruction of justice, according to the US Justice Department.
Jimmy Carter becomes oldest living president in U.S. history
In 2015, Carter was diagnosed with metastatic melanoma that was detected in his liver and spread to his brain. Bush, the 41st US president , died November 30, 2018, 171 days after he reached the age of 94.