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.

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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.

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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.

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This is a developing story.