Memphis Police Director Toney Armstrong told The Commercial Appeal that officers were executing a search warrant around 12:45 p.m. when they were confronted by a dog at a home in north Memphis.
He said one of the officers attempted to shoot the dog, but missed and hit Officer Willie Bryant, 32.
Armstrong said Bryant was in surgery and was listed in critical condition at the Regional Medical Center. Officers blocked off city streets for the ambulance carrying Bryant.
Police have not released the name of the officer who shot Bryant, but said the officer has been relieved of duty pending the investigation into the shooting.
Bryant has been with the department since 2003 and is a member of the Organized Crime Unit. He was wearing a protective vest at the time. A multi-jurisdictional gang unit task force was serving the warrant.