16-year-old boy shot during robbery near Chicago train station on West Side

CHICAGO (CBS)--  A 16-year-old boy was shot during a robbery at the CTA Blue Line stop on Western Avenue Wednesday morning. 

According to the Chicago Fire Department, the shooting took place just before 7 a.m. at 430 South Western Avenue. 

Police said the victim was approached by an offender who demanded his property. When the victim refused, the offender fired shots, hitting the teen in the arm. 

Police sources say the teenager was shot two times and taken to Stroger Hospital in critical condition. 

Sources said the shooting took place inside a vestibule near the turn-style. Police have not confirmed the details on the incident. 

CTA Blue Line trains were bypassing Western Avenue. 

Police are investigating.