CHICAGO (AP) — Police say an argument aboard a Chicago city bus led to a shooting that injured three passengers, two of them teenagers.

Authorities say a 35-year-old man pulled out a handgun and fired several shots after a quarrel escalated between him and two other passengers on the Chicago Transit Authority bus.

The shooting happened Monday in the South Side Chatham neighborhood. An 18-year-old man was being treated for multiple gunshot wounds at the University of Chicago Medical Center. An 18-year-old woman was also taken to the hospital with a wound in the torso.

A Chicago Fire Department spokesman says a 59-year-old man was also grazed on his left side. He took himself to a hospital for treatment.

Authorities say the alleged gunman was taken into custody and being questioned.