It happened around 4:15 Friday afternoon in the area of Argonne Avenue and Main Street in Stanton, Delaware.
Delaware State Police responded to the report of two people bitten. A state trooper arrived and found two dogs attacking a smaller dog.
The officer fired his weapon at the animal, ending the attack.
A 55-year-old mailman was attacked before the incident and suffered multiple wounds from dog bites.
He was taken to Christiana Hospital. No word on his condition.
A 51-year-old woman suffered a dog bite to her upper body but refused treatment at the scene.
Both dogs involved in the attack were taken by the Kent County SPCA and provided with veterinary care. The dog that was attacked remained with its owner.
The incident remains under investigation by the SPCA.