US President Donald Trump's campaign did not conspire with Russia during the 2016 election, a summary of Special Counsel Robert Mueller's report says.

The allegation clouded the first two years of Mr Trump's presidency and his allies see the report's finding as a boost to his re-election chances.

But Attorney General William Barr's summary is inconclusive as to whether Mr Trump obstructed justice.

Opposition Democrats are demanding full access to Mr Mueller's report.

Having repeatedly described the inquiry as a witch hunt, Mr Trump said it was an "illegal takedown that failed".

Despite the inconclusiveness of the report regarding allegations he obstructed justice, the president said it constituted "complete and total exoneration".

The report was the culmination of two years of investigation by Mr Mueller which saw some of the president's closest former aides prosecuted and, in some cases, imprisoned, although not on charges related to the alleged Russian collusion.

What does the summary say?

"The special counsel did not find that any US person or Trump campaign official conspired or knowingly coordinated with Russia," Mr Barr writes.

On the issue of whether justice was obstructed, Mr Mueller's report says: "While this report does not conclude that the president committed a crime, it also does not exonerate him."

In his summary, Mr Barr said the report "ultimately determined not to make a traditional prosecutorial judgment".

There was, he adds, insufficient evidence "to establish that the president committed an obstruction-of-justice offence". (BBC)