Updated

Canadian police say a bus ran off the road in eastern Ontario and at least 24 people have been hospitalized, four with life-threatening injuries.

Ontario Provincial Police Constable Suzanne Runciman said Monday the bus was carrying approximately 37 people, including the driver and a tour guide, when it went off the westbound lanes of Highway 401.

Runciman says she believes tourists were on board.

A manager at Massachusetts-based Union Tour Express says he has heard that one of its buses was involved in the accident, but did not have any further information.

A truck driver who passed by shortly after the crash says he saw passengers standing outside the bus holding bloody noses. He says the bus was sitting in the ditch, up against some rocks.