Democratic presidential candidate Joe Biden has attempted to brush off concerns about his age and health by asking a reporter who had questioned if he would release his medical records: “you want to wrestle?”
The 76-year-old former US vice-president pledged to provide evidence of his fitness for leadership.
But in the exchange with journalists on Friday, he attempted to make light of ongoing worries that he may be too old to take America’s top job.
Asked if he would open his records to assuage concerns, he replied: “What the hell 'concerns', man? You wanna wrestle?”
He added: “There's no reason for me not to release my medical records.”
It came after Thursday’s third primary debate on national TV when rival nominee Julian Castro, 44, appeared to play the age card by suggesting Mr Biden – who would be 78 when he took office – was confused about his own health care proposals.
"Are you forgetting what you said two minutes ago?" Mr Castro asked repeatedly while accusing Mr Biden – wrongly – of becoming mixed up about his own health insurance proposals.
Cory Booker, another younger nominee at 50, went on record after the debate to say there were "a lot of people who are concerned about Joe Biden's ability to carry the ball all the way across the end line without fumbling".
Suggestions about the former Delaware senator’s mental competence have not been helped by a series of gaffes, anachronisms and remarks perceived to show unwitting racism while on the campaign trail.
During Thursday’s debate, he appeared to suggest some black parents should have social workers visiting as a matter of routine, while, at an earlier speech in Iowa he told his audience: "Poor kids are just as bright as white kids".
In the second candidates' debate in July, he was widely mocked after appearing to become confused over the difference between texts and websites. He urged viewers to visit Joe30330. No such site existed. Aids had told him to tell viewers to text Joe30330 it later emerged.
All the same, Mr Biden remains the steady frontrunner over the nine remaining candidates to take on Donald Trump in 2020.
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Speaking on Friday, he acknowledged this "I know I get criticised," he told supporters, "although fewer and fewer are criticising me."