Officers responded to a report at 4:20 p.m. of a disturbance outside the Popeye's Chicken at the corner of Wilson and Broadway.
At least 50 teenagers were fighting, according to Lt. Michael O' Brien.
After police dispersed the teenagers, a group proceeded to the El platform at 4620 N. Broadway, where they resumed fighting.
At that point, at least 20 back-up units arrived to subdue the crowd.
One police officer and one girl were transported to hospitals. There is no word on their condition.
One 18-year-old was arrested as a result of the disturbance, said O' Brien.
A northbound El train was delayed due to the incident.