CHICAGO (CBS)– Two people were injured in an accidental shooting near the Belmont CTA station Thursday morning.

Police said a security guard was on the Red Line right near Belmont when he saw a 16-year-old causing a disturbance.

The security guard walked up to to the teen, which led to a “minor physical altercation.” The gun the security guard was carrying was discharged, hitting him in the leg and the 16-year-old in the stomach.

Both were taken to local hospitals.

An active police investigation is underway, causing Red and Brown Line delays. Red and Brown Line trains are now stopping at Belmont.

This is a developing story.