The Civilian Office of Police Accountability was investigating Sunday after a shot was fired as a teenager struggled with a Chicago police officer who was trying to arrest him on the city's Southwest Side.

Police said at 3:35 p.m. Saturday, a woman called 911 and said a man in a Chevrolet sport-utility vehicle pointed a gun at her during a quarrel.

Officers found a car that matched the woman's description near 71st Street and Lawndale Avenue in the West Lawn neighborhood.

Police arrested the 17-year-old driver, one of multiple males in the car. Officers recovered a gun from the teen, police said.

During the arrest, a second 17-year-old boy, who was a passenger in the vehicle, ran off, police said. As officers tried to take the second teen into custody, a struggle ensued and the officer's gun discharged while concealed in the officer's clothing, police said.

No one was struck by the gunfire, and no injuries were reported, police said.

The second teen was arrested and taken to an area hospital, where he was treated for minor injuries, police said.

Charges were pending against the teens.

COPA and the police Investigative Response Team were investigating, as an officer's gun discharged.