Saugus police say a pedestrian was struck by a car and sent to the hospital with life-threatening injuries Thursday morning.

First responders were dispatched to 190 Main St. at about 10 a.m., where they found the woman on the ground getting aid from an off-duty Cambridge firefighter, according to a release. She was transported to Massachusetts General Hospital with serious injuries that were believed to be life-threatening.

The driver of the vehicle remained on scene and identified himself to officers, police say. The circumstances of the crash are under investigation, and no charges or citations are pending at the time.