ROCKPORT (AP) — Authorities say two men heading to work have been killed when their car struck an ambulance and both vehicles rolled on a rural South Texas highway.

The Texas Department of Public Safety says both people in the car died at the scene before dawn Tuesday on Highway 35 near Rockport.

DPS Sgt. Nathan Brandley says the ambulance had dropped off a patient at a Corpus Christi hospital and was returning to Rockport.

Brandley says it appears the car, carrying two men to work at a nearby plant, failed to yield at a stop sign and hit the ambulance. Two emergency medical personnel in the ambulance suffered injuries not believed to be life-threatening and both men were transported to a hospital.

Names of the two men who died weren’t immediately released.