Two people were arrested but it's unclear if a weapon was recovered, police said.
The two may have been wanted in connection with an earlier armed robbery,
One of the two appeared to be carrying a rifle, police said.
Police approached the two while they were on foot about 9:40 p.m., Alfaro said.
The pair got into a car near the Eisenhower Expressway and Laramie Avenue and drove away before crashing into another car at Lockwood Avenue and Congress Parkway about three blocks away and fleeing on foot, police said.
The incident caused the CTA to cut power to a stretch of the Blue Line between the Pulaski Road and Forest Park stations at 9:46 p.m., said Lambrini Lukidis, a CTA spokeswoman.
Someone entered the CTA right-of-way near Laramie Avenue, she said.
An Illinois State Police K-9 unit and helicopter helped