President Trump's campaign "did not conspire" with Russia during the 2016 election campaign, Special Counsel Robert Mueller's report says.
The summary of the special counsel's report released on Sunday "did not draw a conclusion" as to whether there was any obstruction of justice, either.
It states: "While this report does not conclude that the president committed a crime, it also does not exonerate him".
However, the attorney general says this does not amount to an offence.
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The report is the culmination of two years of investigation by Mr Mueller.
"The report outlines the Russian effort to influence the election and documents crimes committed," the letter by Attorney General William Barr to Congress says.
"The special counsel did not find that any US person or Trump campaign official conspired or knowingly co-ordinated with Russia."
The report was submitted on Friday to Mr Barr, who has been poring over the document.
Congressman Jerry Nadler, the Democratic Chair of the House of Representatives Judiciary Committee, emphasised that the attorney general did not rule out that Mr Trump may have obstructed justice.
"Barr says that the president may have acted to obstruct justice, but that for an obstruction conviction, 'the government would need to prove beyond a reasonable doubt that a person, acting with corrupt intent, engaged in obstructive conduct'."