US attorney general William Barr has said there was “no collusion between the Trump campaign and Russian government hackers” as he spoke ahead of the release of Robert Mueller’s report into Russian election interference.

Eager to get in the last word ahead of the public release of the special counsel’s report, Mr Barr laid out in advance what he said was the “bottom line”.

While Mr Mueller drew no conclusion about whether President Donald Trump had obstructed justice in the investigation, Mr Barr said he and deputy attorney general Rod Rosenstein personally had concluded that while Mr Trump was “frustrated and angry” about the Mueller probe, nothing the president did rose to the level of an “obstruction-of-justice offence”.

Mr Barr said Mr Mueller’s report examined 10 episodes pertaining to Mr Trump and obstruction.

Mr Barr said the president did not exert executive privilege to withhold anything in the report. And he said the president’s personal lawyer had requested and gotten a chance to review the report before its public release.

US President Donald Trump
US President Donald Trump (Susan Walsh/AP)

The Justice Department will release a redacted version of the special counsel’s report later, opening up months, if not years, of fights over what the document means in a deeply divided country.

Earlier, Mr Trump used a tweet to claim the investigation into Russian election meddling was “The Greatest Political Hoax of all time!”.

Mr Barr said he and Mr Rosenstein disagreed with some of Mr Mueller’s “legal theories” pertaining to obstruction of justice, but he said that did not influence their conclusion that Mr Trump did not commit a crime.

He said they set their feelings on the matter aside and accepted Mr Mueller’s “legal framework for purposes of our analysis” but still determined that the evidence gathered by Mr Mueller was “not sufficient to establish” that Mr Trump had violated the law.

Even ahead of the report’s release, Democrats cried foul about Mr Barr’s press conference, for “spinning the report” in the words of Senate minority leader Chuck Schumer.

“The process is poisoned before the report is even released,” he said.

And moments after Mr Barr finished speaking, House judiciary chairman Jerrold Nadler sent a letter requesting that Mr Mueller himself testify before his panel “no later than May 23”.

Mr Barr’s news conference ended abruptly after he bristled at the tone of some questions about how he handled the Mueller report.