A teenage boy was taken to hospital in critical condition Saturday after an incident at an outdoor pool in the Sunnyside area.

Paramedics were called to Sunnyside Pool, near Lakeshore Boulevard and Parkside Drive, at around 6:40 p.m.  

There are conflicting reports as to what exactly happened to the boy. Toronto Paramedic Services said it appeared that the boy struck his head while in the pool. However Toronto police later said they believe the boy may have suffered some sort of medical episode while racing his friends in the pool.

Bystanders said lifeguards performed CPR on the boy until paramedics arrived. He was then rushed to hospital in life-threatening condition.

The city-run pool is popular with bathers, especially during bouts of hot weather. It’s not yet clear exactly how the injury occurred.