A VIA Rail passenger train and a transit bus have collided at a crossing in Canada's capital, Ottawa, reportedly causing "multiple fatalities", according to the Associated Press.

Witnesses say the front end of the double-decker bus was ripped off by the impact.

Ottawa Fire spokesman Mark Messier told CP24 television there are "multiple fatalities" and a number on the bus are injured. Messier said there were no injuries on the train.

The accident occurred just outside a suburban train station in the city's west end in the middle of the morning commute.