MINNEAPOLIS—As the trial of a former police officer charged in the killing of George Floyd nears, Minneapolis is launching a massive security effort to try to prevent a repeat of the rioting and looting that took hold of the city last summer.

Activist groups like Black Lives Matter have said they plan to protest peacefully during the trial but can’t rule out the possibility of civil unrest breaking out in the event of an acquittal. Minnesota Public Safety Director John Harrington said in a briefing Monday that he is coordinating with federal officials to monitor the possibility of extremist groups trying to disrupt the trial but that there is no known imminent threat.

Barricades and barbed wire are rising in the area around the Hennepin County Courthouse, where jury selection in the trial of former officer Derek Chauvin is set to begin Monday.