A security guard accidentally shot himself and a 16-year-old girl Thursday on a CTA Red Line train in Lake View.

About 4 a.m. the 38-year-old guard was on the train in the 900 block of West Belmont Avenue, when he approached the teen who was “causing a disturbance,” Chicago police said.

The pair got into a minor physical altercation which caused the gun the man was carrying in his pocket to fire, striking him in the leg and grazing her on the stomach, police said.

They were both taken to Illinois Masonic Medical Center in good condition, police said.

Area North detectives are investigating.