Black Lives Matter held demonstrations in Minnesota and California on Wednesday to protest police killings of unarmed blacks, dubbing the day "Black Xmas" to show it could affect the economy on one of the busiest shopping days of the year.

"Black communities across the United States are taking brave actions to impede the flow of goods and commerce with peaceful protests to call for an immediate overhaul of the justice system," Black Lives Matter said in a statement on Facebook.

"There will be no business as usual until we get accountability for our dead, and justice for the living," the group said. "Instead of buying gifts to fuel this system, Black Xmas is a day of action."