Donald Trump's former adviser Roger Stone was found guilty on Friday of lying to Congress over his contact with the website Wikileaks.

Stone, a longtime Republican political operative who worked on the US president's 2016 campaign, was found guilty by a jury of all seven charges in the case which included lying to Congress, witness tampering, and obstruction.

The charges against him related to his contacts with Wikileaks, whose publication of Russian-hacked emails from Democrat presidential candidate Hillary Clinton's campaign gave a boost to Mr Trump.

Stone, 67, is the sixth campaign associate of Mr Trump to be convicted as a result of special counsel Robert Mueller's investigation into whether the president's campaign colluded with Russia during the 2016 election.

He has consistently denied the allegations and decried the case as politically motivated.