The station interviewed several people outside the mall who said they had friends sheltering in stores inside.
None of the victims’ injuries appeared to be life-threatening, Wauwatosa Mayor Dennis McBride told ABC News, adding that the shooter was believed to be still at large.
The Journal Sentinel said that the local medical examiner – which is called to scenes with deaths – was not at the mall, which is some six miles outside of Milwaukee, Wisconsin’s largest city.
Wauwatosa police said a press conference would be held later Friday.
The Mayfair Mall was the site of a February shooting in which a city police officer, Joseph Mensah, shot and killed Alvin Cole, a black 17-year-old.