Democratic presidential candidate Joe Biden is facing scrutiny over a dubious tale from the campaign trail, claiming that he was arrested in South Africa while trying to visit Nelson Mandela in prison.

Biden, 77, first told the story at a campaign event in Columbia, South Carolina on February 11, as he tried to shake off defeat in New Hampshire, and has repeated it twice more during outreach to black voters.

'This day, 30 years ago, Nelson Mandela walked out of prison and entered into discussions about apartheid,' Biden said in Columbia of the former South African president, who was imprisoned for 27 years by the apartheid government.

'I had the great honor of meeting him. I had the great honor of being arrested with our U.N. ambassador on the streets of Soweto trying to get to see him on Robben Island,' Biden went on.

No contemporaneous or other supporting evidence has emerged to support Biden's extraordinary claim, leading some to compare it to the so-called 'Mandela Effect', a phenomenon in which a person's vivid memory of a historical event or cultural touchstone turns out to be false.

Democratic presidential candidate Joe Biden (left) claims that he was arrested in South Africa while trying to visit Nelson Mandela (right) in prison

Joe Biden claimed he was arrested in Soweto, a township in Johannesburg, which is nearly 870 miles away from Robben Island, off the coast of Cape Town, where Nelson Mandela was jailed

A prison cell is seen on Robben Island, one of the places were Mandela spent 27 behind bars. Some falsely remember that he died in prison, the so-called 'Mandela Effect'

The Mandela Effect is named for a common false memory that people report, saying they recall Mandela dying in prison in the 1990s. In fact he was freed and went on to become president of South Africa. He died in 2013.

In two retellings of his tale over the past week while campaigning in Nevada, Biden's story changed slightly, dating the purported arrest to before he became engaged in 1977.

On Sunday at a black history awards brunch in Las Vegas, Biden described the happy ending to his story.

'After he got free and became president, he came to Washington and came to my office,' Biden said of Mandela.

'He threw his arms around me and said, 'I want to say thank you.' I said, 'What are you thanking me for, Mr. President?' He said, 'You tried to see me. You got arrested trying to see me.'

Soweto, where Biden says he was arrested, is 900 miles away from Robben Island. A historically and predominately black suburb of Johannesburg, Soweto is famed for the 1976 uprising there in protest of apartheid policy.

Soweto, where Biden says he was arrested, is 900 miles away from Robben Island

On Sunday at a black history awards brunch (above) in Las Vegas, Biden repeated the tale

Biden did repeatedly visit South Africa while he was a U.S. Senator, but no news reports or contemporary accounts have been found mentioning an arrest.

Biden did not mention such an arrest in his 400-page memoir in 2007.

Andrew Young was the U.S. ambassador to the United Nations from 1977 to 1979, and told the New York Times that he had accompanied Biden on several trips to South Africa during that time.

But Young was skeptical that it would even be possible for a sitting member of Congress to be arrested in South Africa back then.

'No, I was never arrested and I don't think he was, either,' said Young, now 87. 'I would not forget going to jail, but I know I did not ever go to jail in South Africa.'

Biden's campaign did not immediately respond to an inquiry from DailyMail.com on Saturday requesting any evidence supporting Biden's claim about the arrest.