The judge overseeing the trial of former Minneapolis police officer Derek Chauvin has blasted a US politician’s criticism of the case, warning she might have given grounds for appeal if Mr Chauvin is convicted.

With the jury in the controversial case retiring on Monday (US time), police across the US are on a knife-edge for the violence that might ignite when the jury returns its verdict in the murder trial against Mr Chauvin.

At a Black Lives Matter rally in Minnesota at the weekend, to protest the recent shooting of Daunte Wright by a police officer, Californian Democrat Maxine Waters further inflamed tensions.

“I hope we get a verdict that says guilty, guilty, guilty,” she said.

“If we don’t, we cannot go away. We’ve got to stay on the street. We get more active, we’ve got to get more confrontational. We’ve got to make sure that they know that we mean business.”

In his final remarks in the Chauvin trial on Monday, Hennepin County District Judge Peter Cahill said it was abhorrent of Ms Waters to tell protesters it would be unacceptable for the former officer to be acquitted of murdering George Floyd.

“I wish elected officials would stop talking about this case, especially in a manner that’s disrespectful to the rule of law and to the judicial branch and our function,” Judge Cahill said after dismissing jurors from the courtroom.

A spokesman for Ms Waters did not immediately respond to a request for comment.

Mr Chauvin, who is white, pushed his knee into the neck of Mr Floyd, a 46-year-old handcuffed black man, in May 2020 for more than nine minutes, sparking protests around the world over police brutality.

Judge Cahill’s remarks came after Mr Chauvin’s defence lawyer, Eric Nelson, requested a mistrial, arguing Ms Waters’ comments had tainted the proceeding.

Mr Nelson noted that the trial had also recently featured in two fictional TV shows and complained of what he described as “threats” against the sanctity of the jury process by Ms Waters.

Judge Cahill denied the request, but called Ms Waters’ comments “abhorrent”. He said the defence’s concerns were legitimate.

“I’ll give you that Congresswoman Waters may have given you something on appeal that may result on this whole trial being overturned,” the judge said.

Ms Waters was in Brooklyn Centre, Minnesota, to show support for protests over the death of Mr Wright, who was shot and killed on April 11 by a police officer during a traffic stop.

Chauvin trial jurors – six of whom are white and six multiracial or black – began deliberating on Monday.

-with AAP