As jurors in the murder trial of ex-policeman Derek Chauvin began its deliberations on Monday, Minneapolis and other cities across the U.S. ramped up security measures, bracing for protests.Chauvin is charged with murdering George Floyd by kneeling on his neck last May.Floyd’s fatal arrest has sparked nationwide anti-racism protests.Minnesota Governor Tim Walz declared a preemptive state of emergency in the Minneapolis metropolitan area and requested security assistance from other states."We cannot allow civil unrest to descend into chaos, we must protect life and property. But we also must understand very clearly: if we don't listen to those communities in pain and those people on the streets many of whom were arrested for speaking a fundamental truth that we must change, or we will be right back here again."Tensions in Minneapolis have been running high over the Chauvin trial, as well as the death of Black man Daunte Wright, who was shot by police during a traffic stop in a suburb of the city.The judge overseeing the Chauvin trial criticized Representative Maxine Waters on Monday, who told protesters over the weekend to "stay on the street" and "get more confrontational" if Chauvin was found not guilty.District Judge Peter Cahill added that her remarks might have given grounds for appeal in the event of a conviction."I wish elected officials would stop talking about this case, especially in a manner that is disrespectful to the rule of law and to the judicial branch and our function."Chauvin's defense lawyer requested a mistrial, arguing that Waters' comments had tainted the proceedings.The request was denied, but he said the concerns were legitimate.