Officers from Philadelphia, Milwaukee and Charlotte, N.C., will join Illinois state troopers and suburban police in keeping demonstrations from turning violent, the Chicago Sun-Times reported Tuesday.
Milwaukee said it is sending 100 officers while Philadelphia has offered 68 members of its police force.
The number of police coming to Chicago from Charlotte-Mecklenburg was not immediately available.
Chicago Police spokesman Melissa Stratton refused to reveal how many out-of-state officers were expected or why those three cities were chosen, the newspaper said.
Stratton said utilizing out-of-state officers for special security events is not unusual.
Last month the Sun-Times reported that as many as 500 Illinois State Police officers would assist Chicago in handling the NATO summit.