Four people were killed and six others injured, including children, when a packed minivan collided Saturday with a tractor-trailer in the Caledon area, just northwest of Toronto.

Ontario Provincial Police Sgt. Chris Whaley said 10 people were in the minivan when it collided with the transport, on Mississauga Road at Charleston Sideroad, in rolling countryside.

Police said two people in the van sustained life-threatening injuries while the other four survivors were not hurt as badly.

Some of the injured were flown to the renowned Hospital for Sick Children in Toronto, while others were taken to Sunnybrook Hospital in Toronto or Orangeville's Headwaters Hospital.

OPP Const. Kent Taylor said the crash was "intersection related, for sure" as crews worked to reconstruct the accident.

Visitors from South Korea in van

There are no stoplights at the junction, which remained closed several hours after the tragedy.

"Our belief is that nine out of the 10 occupants of the vehicle were visitors from South Korea, which of course left something of a language barrier to deal with," said Taylor.

Family members were helping with translation.

Police said the driver of the transport, which was empty at the time, escaped injury.

Police said weather was not believed to be a factor in the accident.