A woman, believed to be in her 30s, is dead after she was struck by a vehicle while riding her bike in Oshawa on Friday morning.

The incident happened in the area of Stevenson Road South and Laval Drive near Highway 401 just before 4 a.m.

The vehicle fled the scene after hitting the cyclist.

The woman was pronounced dead at the scene.

Police said a passerby spotted the cyclist on the pavement and called 9-1-1.

A group of bystanders then surrounded the scene to protect the area until authorities arrived.

There has been no description of the vehicle but police say there is debris at the scene that will hopefully help officers with the identification process.