Eight horses escaped from a southern Ontario farm late Thursday, stampeding down a rural road and galloping into parked vehicles, killing two of the horses and injuring a third.

Halton Regional Police said they were notified at about 11:55 p.m. of a motor vehicle collision involving horses on a road in Milton, Ont., about 50 km west of Toronto.

Tremaine Road and No. 2 Side Road, Milton

Eight horses escaped Celtic Cross stables and began running along Tremaine Road in a group, Sgt. Craig Platt said.

A woman driving on the road saw the stampede and pulled over, but horses ran into her vehicle, killing two of them and "significantly" damaging the vehicle.

Police used cars to block the roadway and to keep the horses away from nearby train tracks.

"Our perimeters had to be re-evaluated and moved constantly, because the horses were continuously moving as well," Platt said.

Horses attempt leap over police vehicle

Aggravated by the police vehicles and a passing train, the spooked horses stampeded toward a parked police car.

'To have eight [horses] in one group running in the same direction and then coming into contact with a vehicle is very unnerving.'— Sgt. Craig Platt, Halton Regional Police

"Two of the horses actually attempted to leap over that service vehicle," Platt said. "One horse made contact with the back of that car and made significant damage to that vehicle."

The back window was smashed out and the car's rear left was severely dented. The officer and his police dog were not hurt.

A veterinarian was called in to treat the leaping horse, which may have to be killed because of its injuries.

The five remaining horses were rounded up by uniformed and tactical police officers "after a considerable amount of effort" over several hours, and returned to their farm with the help of the owners.

The owners weren't speaking to media Friday, except to say it had been a difficult day.

No one was injured during the stampede, though the woman in the first car was shocked, Platt said.

"To have eight in one group running in the same direction and then coming into contact with a vehicle is very unnerving," he said.

No charges have been laid. It's not known how the horses escaped.