The Saskatchewan Penitentiary is currently in lockdown.
The move was made after two inmates were assaulted in the medium-security wing around 9:45 last night.
Prison spokesman Darcy Begrand says the pair approached staff, who noticed they had “visible signs of injury”.
One of the injured inmates was treated on site, while the other was taken by ambulance to hospital, where he remains.
Begrand says visits have been suspended while cells are searched.
He expects the lockdown to remain in effect for at least a couple of days.