Durham Regional Police were called to the Sheridan Veterinary Services at 1398 Kingston Road in Pickering at around 7:30 a.m. regarding an armed robbery in progress.
The officer fired several shots during a confrontation and the young male suffered at least one gunshot wound, according to the Special Investigations Unit, the Ontario police watchdog which is now investigating the incident.
The teen was then taken to Rouge Valley Health System and then transferred to Sunnybrook Health Sciences Centre in Toronto with life-threatening injuries.
Kingston Road will be closed for a few hours between Glennanna Road and Glengrove Road while the investigation continues.
The SIU is called in to investigate whenever someone is killed or seriously hurt while interacting with police.