PRINCE GEORGE, B.C. -- Nine people aboard a Greyhound bus were transported to hospital Thursday after the vehicle flipped on its side beside an icy highway south of Prince George, B.C.

RCMP Cpl. Dave Tyreman said the bus lost control on Highway 97 just before 8 a.m., crossed the centre line and ended up in a ditch.

The bus, which was towing a trailer, was northbound on its way to the central B.C. city of Prince George from Kamloops in the Interior.

"There were nine people onboard," said Tyreman. "That was the driver of the bus and eight passengers. All of them were taken to the hospital."

He said three had serious but non-life-threatening injuries and the other six had minor injuries.

B.C. Emergency Health Services spokeswoman Preet Grewal said five ambulances rushed to the scene.

Greyhound Canada spokeswoman Lanesha Gipson said the company was trying to gather information about the crash.

Tyreman said a RCMP traffic service analyst, an accident reconstruction expert and a commercial-vehicle safety inspector are investigating the cause of the crash.

He said it was snowing moderately when he arrived at the scene. He said some sections of the highway, while decent, were a little bit icy, adding the temperature had dipped to -1C overnight.

"A lot of times in the wintertime you do find black ice," he said.

Highway 97 was closed or partially closed to vehicles most of Thursday morning while investigators went over the scene.