MINNEAPOLIS (REUTERS) - Minneapolis and other US cities were ramping up security measures on Monday (April 19), girding for possible protests after a jury delivered a verdict in the trial of former Minneapolis police officer Derek Chauvin, charged with murdering George Floyd by kneeling on his neck.

Citing the "threat of civil unrest," Minnesota Governor Tim Walz declared a preemptive state of emergency in the Minneapolis metropolitan area and requested security assistance from other states.

Local officers were stretched, he said, having policed a week of protests over the fatal police shooting of a Black man in a Minneapolis suburb and bracing for more protests over the Chauvin trial verdict.

At a news briefing, Mr Walz said "systemic changes" were necessary to protect Black Americans but said, "We cannot allow civil unrest to descend into chaos. We must protect life and property."

A jury began deliberating charges of third and second-degree murder and second-degree manslaughter against Chauvin after a tense, three-week trial featuring bystander video of Floyd's fatal arrest that launched a national anti-racism protest movement last May.

Minneapolis and state officials have heightened security precautions, girding the courthouse tower with barbed wire and armed soldiers from the National Guard.

A few miles from the courtroom, nightly protests have flared in Brooklyn Centre, Minnesota, over the police shooting of a 20-year-old Black man, Mr Daunte Wright, after a routine traffic stop on April 11.

Officer Kimberly Potter turned in her badge on Tuesday, and has been charged with manslaughter.

Minnesota police were criticised for detaining and pepper-spraying journalists at Brooklyn Centre protests on Friday, and department leadership responded on Saturday by promising to no longer detain, threaten or rough up members of the media covering the unrest.

The Minnesota State Patrol also agreed to stop photographing journalists and their credentials and will no longer order where reporters can position themselves to cover the demonstrations.

"Following feedback from media, and in light of a recent temporary restraining order (TRO) filed in federal court, MSP will not photograph journalists or their credentials," the Minnesota State Patrol statement said.

It said journalists would be exempt from general dispersal orders issued to demonstrators, and that state police were banned from using chemical spray against the press.

The American Civil Liberties Union of Minnesota, which won the restraining order, said the behaviour of some officers "went beyond unlawful detention to include outright retaliatory assault" against journalists, whose work to inform the public is protected by the US Constitution.

Cities on alert

In Washington DC, where thousands protested Floyd's death last June, the National Guard said it was activating about 250 personnel to help police with street closures in the city ahead of the verdict.

New York City Police Commissioner Dermot Shea told local media last week that his department, which critics said cracked down brutally on protests last spring, had been preparing for the Chauvin trial verdict and doing "a lot of work" engaging with local leaders, clergy and community organisations.

"We're just asking anyone that may come out to voice their concern over this trial...do it peacefully, no property damage and we'll get through it together," Mr Shea said.

In Chicago, the third-largest US city, the police department said it deployed additional resources throughout the city including downtown, and cancelled days off for police officers in several units and teams.

Illinois Governor JB Pritzker said he was activating 125 personnel from the state's National Guard to support the city's police starting Tuesday.

Chicago businesses have boarded up windows in anticipation of possible unrest, particularly after graphic body-camera video was released last week showing a Chicago police officer fatally shooting a 13-year-old Black boy. Chicago saw widespread looting following Floyd's death last May.

Florida Governor Rick DeSantis, a Republican, on Monday signed an "anti-riot" Bill into law, with tougher penalties for people who engage in violent protests, noting his expectation of potential fallout from the Chauvin verdict.

The law enhances penalties for crimes committed during a riot or violent protest, allowing authorities to detain protesters until their first court appearance, and establishes new felonies for organising a violent protest.