The daughter of the late former US President Ronald Reagan has said there is "no defence" for racist comments he made in a 1971 phone conversation.
Newly unearthed tapes reveal Reagan - then Governor of California - described UN African delegates as "monkeys".
His daughter Patti Davis condemned the remarks in a newspaper article.
"There is no defence, no rationalisation, no suitable explanation for what my father said," she wrote.
Ms Davis wrote in an article for the Washington Post that she was preparing to defend her father before she heard the tapes, but was appalled to hear what the former president said.
"I can't tell you about the man who was on the phone," she writes. "He's not a man I knew."
What did Ronald Reagan say?
He was referring to Tanzanian delegates at the UN, who had just sided against the US in a vote to recognise China and expel Taiwan.
Reagan - a supporter of Taiwan - called the president the next day, telling him: "To see those... monkeys from those African countries - damn them, they're still uncomfortable wearing shoes!"
Nixon can be heard laughing loudly after the comments.
What did Reagan's daughter write?
Patti Davis said the tapes shocked her. "I wanted to immediately go back in time to before I heard my father's voice saying those words."
Her father, she wrote, stood up against segregation when he played football in college and later on when he was in office, when given membership to "a ritzy country club in Los Angeles".
"He turned it down because the club didn't allow Jews or African Americans."
Regardless, she wrote that the words she heard "will stay with me forever", and said her father if alive "would have asked for forgiveness" if he had heard the recording.
His comments "cannot be interpreted as anything but ugliness", Ms Davis wrote. She added that she hopes people will forgive the former president "for words that should never have been uttered in any conversation," and which "for those of us who knew Ronald Reagan, will always be an aberration."
Critics accused Reagan of racism throughout his career.
When running for California governor in 1966, the former actor said that "if an individual wants to discriminate against Negroes or others in selling or renting his house, it is his right to do so".
As president, he tried to block a bill that would impose sanctions on apartheid South Africa. The House overrode his veto.
Reagan denied any suggestions he was racist