San Diego's police chief says an officer's fatal shooting of a pit bull is being reviewed internally to determine if authorities acted properly.

Shelley Zimmerman said Friday that such internal reviews are done for any shooting involving a police officer. She didn't elaborate on the shooting but her department has said the officer shot the dog as a last resort to prevent himself from being bitten.

The department says officers responded last Sunday to a domestic violence call involving allegations of strangulation in the city's Pacific Beach neighborhood. It says the owner failed to restrain the dog after trying to block the animal from leaving the resident.

Police say the officer tried to retreat before firing the gun.