A three-year-old toddler was killed inthe backyard of herdaycare on Île Perrot,west of Montreal Island Wednesday after a speeding car crashed through the fence.

The girl'sbabysitteris in deep shock and two teenaged drivers are in police custody facing dangerous driving charges in connection to the tragedy, provincial police said.

The accident happened at the corner of Érables and Giffard streetson Île Perrotjust after lunch, police say.

A car driving on Érables Street came to a full stop at the corner of Giffard and started to turn left when a second vehicle sped up from behind and tried to pass it, said police spokesman Ronald MacKinnis.

The second car hit the first and the collision was so hard that both spun out of the intersection into a nearby yard, where one vehicle crashed through the backyard fence.

The three-year-old was playing behind the fence and was struck.

She was declared dead after being rushed to the Lakeshore Hospital.

The babysitter, who witnessed the whole accident, "was literally beside herself" with shock by the time police arrived, MacKinnis said.

She's being treated at the Valleyfield Hospital.

Speeding was definitely a factor and police are investigating other causes as well, MacKinnis said.

The driver and passenger,aged 17 and 18, were arrested and taken to police headquarters for questioning.