The man is considered armed and dangerous, according to police.
Officers were dispatched to the area near Montreal Street and Highway 401 around 8:45 a.m. Saturday due to an alleged altercation involving the use of a pistol.
The man is described as a white male in his twenties wearing a white shirt and blue pants.
Authorities have blocked off much of the area, using canine units to help search for the man.
According to the police statement, the man fled via Virginia Street or Compton Street.
People are urged to avoid the area, residents being urged to lock their doors and windows.
Those with information on the whereabouts of the man are urged to call 911 and not to approach him.
Reports can be made anonymously by calling 613-549-4660 ext. 0.
With information from CBC News