Three people have been killed and 23 others injured, some of them critically, when a double-decker bus crashed into a bus shelter at Westboro station in Ottawa in the middle of a Friday evening rush hour.

The most serious injuries occurred on the top right side of the bus, following its collision with the platform at around 4:00pm Friday. Emergency workers immediately rushed to the scene to rescue passengers who were trapped on the upper level. Video footage showed firefighters using ladders to get people out, in an operation which took more than two hours to complete.

Two passengers and one person waiting on the platform died, Ottawa Mayor Jim Watson told reporters, adding that 23 others were injured in the crash, which he described as "horrific." Local news stations report that at least seven of the injured are in critical condition.

Authorities have launched an investigation into the cause of the collision, detaining the driver of the OC Transpo bus for questioning.

@CBCOttawa here is a video of the bus crash scene at the Westboro station pic.twitter.com/lCvqvgIWmE — Blue and White (@greatuncleRB) January 11, 2019

LATEST INFORMATION: 3 fatalities, 23 injured in Westboro bus crash. Two people on the bus were killed. The third person was standing on the platform. The driver of the bus has been detained by police. It happened @ 3:50 pm. #ottnews#ottawa#buscrash#westboro#octranspopic.twitter.com/k58X9JF6O2 — Stefan Oliver Keyes (@Stefan_Keyes) January 12, 2019

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