REVERE – An ambulance possibly on its way to an emergency struck a car before crashing into a Revere house early Sunday morning, according to Revere Police.Sgt. John Nelson of Revere Police said a witness at a bus stop told authorities he saw a Cataldo ambulance clip the rear of a black Honda Civic driving down Broadway before it careened into the front of a house on the corner of Broadway and Mountain Avenue around 3:30 a.m.Two Haverhill residents were in the Civic at the time of the crash, Nelson said. Three people went to Whidden Hospital with non life-threatening injuries, he said.The ambulance ripped off a portion of the house?s facade but, Nelson said, National Grid determined there were no gas leaks and a building inspector deemed the home safe to enter.The ambulance, which was not transporting a patient, had its lights on but no sirens, and Nelson said it may have been heading to a call at the time of the crash.A call to Cataldo Ambulance was not returned.Taylor Provost can be reached at [email protected].