A federal judge on Thursday denied a bid for a new trial by President Donald Trump's longtime friend and adviser Roger Stone after the veteran Republican operative accused the jury forewoman of being tainted by anti-Trump political bias.

US District Court Judge Amy Berman Jackson rejected Stone's claim that the jury forewoman was biased against Trump and therefore could not be impartial in deciding Stone's guilt or innocence during the trial.

The Republican president has assailed the judge and prosecutors in the case and has labeled the forewoman an 'anti-Trump activist.'

Stone's request for a new trial 'is a tower of indignation, but at the end of the day, there is little of substance holding it up,' Jackson said in an 81-page decision.

Jackson sentenced Stone on February 20 to three years and four months in prison after a jury convicted him on November 15 on seven counts of obstruction of justice, witness tampering and lying to lawmakers investigating Russian interference in the 2016 US election.

The charges stemmed from former Special Counsel Robert Mueller's inquiry that documented Moscow's meddling to boost Trump's candidacy.