The resignations on Tuesday from Officer Kim Potter and Police Chief Tim Gannon came two days after the death of 20-year-old Daunte Wright in Brooklyn Center.

Potter, a 26-year veteran, had been on administrative leave following Sunday's shooting, which happened as the Minneapolis area was already on edge over the trial of an officer charged in George Floyd's death.

Brooklyn Center Mayor Mike Elliott said at a news conference the city had been moving toward firing Potter when she resigned.

Elliott said he hoped her resignation would "bring some calm to the community," but that he would keep working toward "full accountability under the law".

"We have to make sure that justice is served, justice is done. Daunte Wright deserves that. His family deserves that," Elliott said.

A decision on whether prosecutors will charge Potter could come as soon as Wednesday. Meanwhile, the cities of Brooklyn Center, Minneapolis and St. Paul imposed 10pm curfews.

Protesters began gathering again on Tuesday at the city's heavily guarded police headquarters, now ringed by concrete barriers and a tall metal fence, and where police in riot gear and National Guard soldiers stood watch.

Gannon has said he believed Potter mistakenly grabbed her gun when she was going for her Taser. She can be heard on her body camera video shouting "Taser! Taser!"

However, protesters and Wright's family members say there's no excuse for the shooting and it shows how the justice system is tilted against Blacks, noting Wright was stopped for expired car registration and ended up dead.

Wright was stopped for having expired license plates. Police then tried to arrest him on an outstanding warrant after failing to appear in court on charges that he fled from officers and possessed a gun without a permit during an encounter with Minneapolis police in June.

Body camera footage released on Monday shows Wright struggling with police when Potter shouts, "I'll Tase you! I'll Tase you! Taser! Taser! Taser!"

She draws her weapon after the man breaks free from police outside his car and gets back behind the wheel.

After firing a single shot from her handgun, the car speeds away, and Potter says, "Holy (expletive)! I shot him."

Wright died of a gunshot wound to the chest, according to the medical examiner.

Protests began within hours.

In her one-paragraph letter of resignation, Potter said, "I have loved every minute of being a police officer and serving this community to the best of my ability, but I believe it is in the best interest of the community, the department, and my fellow officers if I resign immediately."

Wright's father, Aubrey Wright, told ABC's "Good Morning America" that he rejects the explanation that Potter mistook her gun for her Taser.

"I lost my son. He's never coming back. I can't accept that. A mistake? That doesn't even sound right. This officer has been on the force for 26 years. I can't accept that," he said.

Chyna Whitaker, mother of Daunte's son, said at a news conference she felt police "stole my son's dad from him".

The Minnesota Police and Peace Officers Association said in a statement on Tuesday that "no conclusions should be made until the investigation is complete".

Elliott, the mayor, called for the governor to move the case to the attorney-general to prosecute.

Australian Associated Press