WASHINGTON: Derek Chauvin, the white ex-policeman convicted of murdering African-American man George Floyd, asked Tuesday for a new trial on claims of jury and prosecution misconduct.

The 45-year-old -- who knelt on Floyd's neck for more than nine minutes in Minneapolis -- faces up to 40 years in prison after being found guilty last month in a case that prompted a national reckoning on racial injustice and police brutality.

Chauvin's attorney Eric Nelson argued that his client did not get a fair trial due to publicity around the case, court and prosecution errors, as well as "race-based pressure" on the jury.

He also alleges that jurors should have been isolated during the trial and that the case could only get a fair hearing in a different place.

"The publicity here was so pervasive and so prejudicial before and during this trial that it amounted to a structural defect in the proceedings," Nelson wrote.

Civil rights attorney Ben Crump, who represents the Floyd family, fiercely opposed the motion on Twitter: "No. No. No. Guilty. Guilty. Guilty."

The filing came as the impartiality of a juror in the case has been called into question after a photo surfaced of him at an anti-racism rally.

Legal experts had said Chauvin's defence attorney could potentially use the photo of juror Brandon Mitchell as grounds to appeal the verdict, though the matter was not mentioned in Tuesday's pleading.