About 40 people were arrested on Monday as unrest continued for a second night after a Black man was shot dead by a police officer in Brooklyn Center, the U.S. state of Minnesota, according to the police.

Police said Daunte Wright, 20, was shot and killed on Sunday after a police officer mistook her gun for a taser during a traffic stop.

The shooting has sparked two nights of protests in Minnesota, even after a curfew was imposed from Monday night until Tuesday morning. 

The police officer who fatally shot Wright and the police chief who called the case an apparent accident resigned on Tuesday.

Brooklyn Center Mayor Mike Elliott told reporters the City Council had passed a resolution calling for the dismissal of both the chief, Tim Gannon, and the officer in question, Kim Potter, a 26-year veteran of the police force.

"I'm hoping this will bring some calm to the community," Elliott said. "We want to send a message to the community that we are taking this situation seriously."

The mayor said he had yet to accept Potter's resignation. Terminating Potter's employment, rather than allowing her to resign, could adversely affect her pension and ability to find work in law enforcement elsewhere, reported Reuters.