One person was shot in the torso, one on the leg and the third in the foot. They were all rushed to University Hospital with non-life threatening injuries, according to officials.
Eyewitness News is told one of the victims was shot on the 20th floor and another on the third floor. Another was found outside the building.
The gunman fled the scene and no arrests were immediately made.
The building is a high-rise apartment complex that also houses a pre-school.
