PARRY SOUND, Ont. -- Provincial police say all the passengers in an SUV have died after the vehicle slammed into a tractor trailer north of Parry Sound, Ont., on Tuesday.

Police say the SUV was so thoroughly destroyed after it veered into an oncoming lane of traffic and hit the truck that they don't yet know how many people were in the vehicle.

Sgt. Carlo Berardi says the SUV was fully engulfed in flames when emergency crews arrived at the scene on Highway 69 in Shawanaga First Nation at about 4 p.m.

He says investigators with Toronto's Centre of Forensic Sciences are assisting with the case and will notify police when they've determined the number of victims and their identities.

Police say the driver of the transport truck was not injured and they don't expect to lay any charges in the incident.

Highway 69 was closed for more than seven hours for the investigation, which police say is still ongoing.

"I'm unaware that weather would have affected this crash," Berardi said, adding that it was sunny and clear at the time of the collision.