The Justice Department said Sunday that special counsel Robert Mueller's investigation did not find evidence that President Donald Trump's campaign "conspired or coordinated" with Russia to influence the 2016 presidential election.
Mueller also investigated whether Trump obstructed justice but did not come to a definitive answer, Attorney General William Barr said in a letter to Congress summarising Mueller's report.
The special counsel "does not exonerate" Trump of obstructing justice, Barr said, and his report "sets out evidence on both sides of the question."
After consulting with other Justice Department officials, Barr said he and Deputy Attorney General Rod Rosenstein determined the evidence "is not sufficient to establish that the president committed an obstruction of justice offense."
Barr released a four-page summary of Mueller's report Sunday afternoon.
Mueller wrapped up his investigation on Friday with no new indictments, bringing to a close a probe that has shadowed Trump for nearly two years.
Barr's chief of staff called White House counsel Emmet Flood to brief him on the report to Congress. Trump was at his Mar-a-Lago resort in Florida, about to return to Washington after spending the weekend there.
Mueller's investigation ensnared nearly three dozen people, senior Trump campaign operatives among them.
The probe illuminated Russia's assault on the American political system, painted the Trump campaign as eager to exploit the release of hacked Democratic emails to hurt Democrat Hillary Clinton and exposed lies by Trump aides aimed at covering up their Russia-related contacts.
Mueller submitted his report to Barr instead of directly to Congress and the public because, unlike independent counsels such as Ken Starr in the case of President Bill Clinton, his investigation operated under the close supervision of the Justice Department, which appointed him.
Mueller was assigned to the job in May 2017 by Rosenstein, who oversaw much of his work. Barr and Rosenstein analysed Mueller's report on Saturday, labouring to condense it into a summary letter of main conclusions.