Former Vice President Joe Biden conceded Friday that he should not have challenged an Iowa voter to a push-up contest during an angry exchange in which he mocked the man as a “damn liar” and “fat.”

During a town hall in New Hampton, Biden became angry when a farmer pressed him about allegations of corruption against his son, Hunter Biden, whose lucrative board membership at Burisma Holdings, a Ukrainian energy firm, is the center of a Senate investigation.

The voter, who declined to give his name, pressed Biden on why it was acceptable for Hunter to capitalize on his father’s power while Democrats assail President Trump for self-dealing.

“You’re a damn liar, man, that’s not true,” Biden boomed as the man continued to argue that “you don’t have a backbone… any more than Trump.” When the man finally told Biden he wouldn’t vote for him, Biden replied, “I knew you weren’t voting for me.”

Separately, the man told the 77-year-old Biden that he worries the former vice president is too old for the White House. Biden challenged the man to a pushup contest and an IQ test. The man later told reporters that he prefers Sen. Elizabeth Warren (D-MA).

“I probably shouldn’t have challenged him to pushups,” Biden told reporters ahead of a campaign event with former Secretary of State John Kerry, conceding that difficult questions are par for the court for presidential candidates.

In an attempt to quell the blowback from the former vice president fat-shaming the voter, a senior Biden campaign said that the candidate used the word “facts” instead of “fat” before launching into a tirade against the man.

“Let’s be clear RE: the exchange VP Biden had with a voter in Iowa earlier today: 1) the gentleman is a self-identified Warren supporter who said he would vote for the VP in a general election 2) his facts were flat-out wrong and 3) the crowd backed VP Biden up in his response,” Symone Sanders tweeted. “Any assertion VP Biden said a word about the gentleman’s appearance is making this something it is not. In the latter part of the exchange, the VP began to say “Look, facts” then said “here’s the deal.” If you’ve been to a Biden event, you’ve heard this before.”

After the event, one attendee confronted the voter and their exchange nearly devolved into a physical confrontation.

Biden is “senile, anyhow,” the farmer told the Washington Examiner after the confrontation deescalated.

The Associated Press contributed to this report.