US President Donald Trump has weighed in on the case of his longtime adviser saying he has a "'very good chance of exoneration" after Roger Stone was sentenced to three years and four months in prison.

Stone was convicted of lying to Congress, witness tampering and obstructing the investigation into alleged Russian interference in the 2016 presidential elections.

Stone was facing a much longer sentence until Trump tweeted about his case.

Al Jazeera's John Hendren reports from Washington, DC.