A news release from the Ontario Provincial Police says the charges were laid "after an incident at the Blue Water Bridge" at 7:30 p.m. ET Saturday.
A 19-year-old woman, a 24-year-old man and a 26-year-old man each face charges of possessing a loaded, prohibited firearm, of importing a prohibited weapon into Canada and possessing a quantity of cocaine for the purpose of trafficking.
The accused are due to appear in court on Monday.
Police say they are not releasing any further information at this time.