Washington: Virginia Governor Ralph Northam has denied he was in a racist photo that appeared in his 1984 student yearbook page after initially apologising for it.
Northam said he recognised that people would find this "hard to believe", the BBC reported on Saturday.
He also admitted blackening his face to impersonate singer Michael Jackson at an event in the same year. Top US Democrats have called on him to resign. But he says he will stay on.
The picture showed a man in blackface and another man in Ku Klux Klan robes.
Former Vice-President Joe Biden said Northam had lost all moral authority. Black politicians in Virginia called it "disgusting" and Republicans also urged him to resign.
He said he had initially taken responsibility for the photo, which he described as "clearly racist and offensive".
But he said that on reflection with his family and friends he had concluded that he was neither of the people in the photo.
"It has taken time to make sure that it's not me but I'm convinced I'm not on that photo," he said.
He said that he had however blackened his face at a dance contest in San Antonio. "It is because my memory of that is so vivid that I do not believe I am in the photo in the yearbook," he said.
Northam said he was not asking for forgiveness for his past actions but for "the opportunity to demonstrate without a shadow of a doubt that the person I was then is not the person I am today".
The statement on Saturday came after he said on Friday that he was "deeply sorry for the decision I made to appear as I did in this photo and for the hurt that decision caused then and now".
Northam's yearbook page, which came from the paediatric neurologist's time at Eastern Virginia Medical School, was first published by conservative website Big League Politics.
The Virginian-Pilot newspaper tweeted a picture of the page which it said it obtained from the medical school library.
An official from the medical school verified the photo and told the Huffington Post that it had come from a "student-produced publication".