Speaking before Mr Mueller took to the podium during a live news conference, Attorney General William Barr said the report confirms the Russian government sought to meddle in the 2016 vote. But he added the special counsel found no evidence of any American conspiring with Vladmir Putin's government. And Mr Barr said the special counsel did not find proof any person illegally disseminated hacked emails.

Mr Barr said President Trump’s personal counsel had been given the chance to read the report before it was released.

He added that “evidence of non-corrupt motives” weigh against allegations that the President obstructed justice.

He also said the White House “fully cooperated” with the investigation.

Mr Trump marked the Mr Barr's comments with a Game of Thrones themed tweeting, writing: "No collusion. No obstruction. For the haters and the radical left democrats - GAME OVER."

Mr Barr also warned that “significant portions” of the report could have been kept secret because of of executive privilege, before adding it was his decision to go public with the document.

The report's disclosure, with portions expected to be blacked out by Barr to protect some sensitive information, is certain to launch a new political fight in Congress and on the 2020 presidential campaign trail, as Trump seeks re-election in a deeply divided country.

"PRESIDENTIAL HARASSMENT!" the Republican president wrote in one of a series of Twitter posts ahead of the release attacking the Mueller inquiry and Democrats.

The report promises to provide new details about some of the biggest questions in the investigation, including the extent and nature of his campaign's interactions with Russia and actions President Trump may have taken to hinder the inquiry including his 2017 firing of FBI Director James Comey.

Mr Mueller submitted the report to Mr Barr on March 22. Two days later, Barr told lawmakers the inquiry did not establish that Trump's 2016 campaign team engaged in a criminal conspiracy with Russia and that Mueller had not exonerated Trump of committing the crime of obstruction of justice.

Mr Barr subsequently concluded that Trump had not committed obstruction of justice.

Mr Barr said he and Attorney General Rod Rosenstein, who appointed Mr Mueller as special counsel in May 2017, "disagreed with some of the special counsel's legal theories and felt that some of the episodes examined did not amount to obstruction as a matter of law."

Mr Rosenstein appointed Mueller as special counsel in May 2017.

Mr Barr said that Mr Mueller's report recounts 10 episodes involving President Trump and evaluates whether they qualified as obstruction of the probe into Russian interference in the 2016 presidential election.