A security guard accidentally shot himself and a 16-year-old girl early Thursday when he approached the teen about a disturbance on a Red Line train near Belmont, police said. The guard has been licensed to work as an armed security guard for about two weeks, according to state records.

Police said the girl was causing a disturbance aboard a southbound train when the 38-year-old guard approached her shortly before 4 a.m. A “minor physical altercation ensued,” police said, which caused a handgun the guard carried in his pocket to discharge.

The guard was shot in his left leg and the girl’s stomach was grazed, according to police.

Officers located the guard minutes later on the 3100 block of North Sheffield. The girl remained at the train station. Ambulances transported both of them to Advocate Illinois Masonic Medical Center in good condition, police said.

State records show that the guard received his license to carry a firearm during security work on Mar. 23.

Many other questions remain unanswered: Was the guard working for CTA? If so, did CTA hire him as armed security or did he bring the gun along on his own? Why was the gun in his pocket and not in a holster? And, importantly, why did he leave the scene?

Area North detectives are investigating the case.