A potential running mate for Donald Trump in the US election has continued to defend shooting dead her family's puppy after saying the animal was "extremely dangerous".

South Dakota governor Kristi Noem has told Fox News the 14-month-old wirehaired pointer, who was named Cricket, was a "working dog" and "not a puppy". She said in the interview that the female dog had "come to us from a family who had found her way too aggressive.