Provincial police say a six-year-old Alliston girl is dead and her 36-year-old father is seriously injured after a collision on Monday morning.

Police say the two-vehicle crash occurred in Caledon, just after 10 a.m. between Charleston Sideroad and Old Base Line Road.

Police say the car the father and daughter were in was hit from behind by a tractor-trailer.

No one in the tractor-trailer was injured.

Police are asking anyone who may have seen the collision or have dashcam video to contact them.