By JIN YU YOUNG AND MICHAEL WILSON | THE NEW YORK TIMES

Two police officers, who had been following up on a traffic violation, were killed in a shooting ambush Sunday evening outside a house in an upstate New York town near Syracuse, authorities said.

The officers, of the Syracuse Police Department, attempted to stop a vehicle around 7 p.m. Sunday. The driver fled, but the officers used the vehicle’s license plate to track it to a house in Liverpool, a village in the suburban town of Salina. When the officers learned that the vehicle’s driver might be armed, they requested assistance, and deputies from Onondaga County arrived, Chief Joseph L. Cecile of the Syracuse Police Department told reporters at a news conference Monday morning.

Onondaga County Sheriff's Lieutenant Michael Hoosock and Syracuse Police Officer Michael Jensen.

The officers found the parked vehicle and saw ammunition inside, according to Onondaga County District Attorney William J. Fitzpatrick. A deputy approached the house from the rear, while two police officers approached from the front, Fitzpatrick said. Officers then “heard what sounded like someone manipulating a firearm from inside the residence” before shots rang out, Cecile said.

The deputy at the back of the property was shot, as was one of the officers in the front. Officers returned fire, striking the shooter, identified by the district attorney as Christopher Murphy, 33.

Murphy and both officers were later pronounced dead at a nearby hospital. The two officers have not been publicly identified.