New York City police say a gunman ambushed and killed an officer in what the police commissioner called a "clear assassination" before backup arrived and shot the attacker dead.

NYPD Sgt. Brendan Ryan says the victim, 48-year-old Miosotis Familia, died at a hospital early Wednesday. Familia had been on the force for 12 years and was a mother of three.

Police say other officers shot and killed the suspect, who was brandishing a revolver. A stray bullet also struck another person, believed to be a bystander, who is in stable condition.

The attack happened in the Bronx's Fordham Heights neighborhood around 12:30 a.m., while Famlilia was sitting in her vehicle, a mobile command unit. She and her partner had been stationed there after a rash of crimes in the neighborhood.

Recordings of the radio call show Familia's partner screaming for backup and an ambulance.

Other officers spotted and pursued the suspect, identified as Alexander Bonds, 34.

Bonds had a criminal record including six prior arrests. He was on parole for a 2014 robbery in Syracuse, New York.