York Regional Police confirm two people have been killed in a serious crash involving as many as eight vehicles.
It happened around 2:20pm on Ravenshoe Road on the outskirts of Keswick.
Police closed that section of road between Warden and Woodbine, and have indicated it will stay closed for some time.
There's no information on what led to the crash, but police have admitted that stretch of road is very straight, with no homes or businesses around, so they often see speeding through there.
Nothing yet on the identities of the victims.