The Milwaukee Journal Sentinel said a crowd had gathered outside for the funeral when a vehicle drove up to the location and a gunman opened fire.
The victims, who ranged in age from 20 to 48, were transported to a local hospital where each was in stable condition, the MPD said.
“The circumstances surrounding this incident are still under investigation and we are seeking an unknown suspect,” the department said, asking for anyone with information to reach out to police.
Milwaukee Mayor Tom Barrett said the shooting was “an example of the insanity that we’re seeing with the number of guns, particularly illegal guns, on the streets in the city of Milwaukee.”
“After four consecutive years of reductions in homicides and non-fatal shootings, this year we have seen a dramatic increase here in the city of Milwaukee and it is not acceptable to me, it’s not acceptable to the residents of this city and I know it’s not acceptable to the police chief and the members of the police department,” he added.