They say a man in his mid-20s has been arrested in connection with the Halloween night attacks and taken to hospital.

Police had earlier warned residents to remain indoors as they hunted for a man dressed in medieval clothing and armed with a bladed weapon who had left "multiple victims", CTV News reported.

Spokesman Etienne Doyon said police were first notified of the stabbings near the national assembly shortly before 10:30 p.m. Saturday.

The five injured victims were taken a local hospital, and a spokeswoman said their lives did not appear to be in danger.

Police asked area residents to remain indoors as their investigation was ongoing.