Former US vice president Joe Biden has apologised for telling a radio host he "ain't black" if he was still weighing whether to support him or Donald Trump in the US presidential election.
The likely Democratic nominee's remarks to The Breakfast Club co-host Charlamagne tha God in an interview broadcast on Friday drew a swift rebuke from the Trump campaign and Republican supporters, as well as some Democrats on Twitter.
"I shouldn't have been such a wise guy," Biden said on a subsequent call with the US Black Chambers Inc, an African-American business group.
"I shouldn't have been so cavalier."
Biden, who served eight years as No.2 to former US president Barack Obama, added he has never taken black voters for granted and that no one should have to vote for somebody.
During the radio interview, recorded on Thursday, the popular host had challenged Biden over his long history on race issues.
As Charlamagne pressed Biden about whether he would select an African-American woman as vice president, a campaign aide could be heard trying to end the interview.
"You can't do that to black media!" the radio host said.
Biden responded: "I do that to white media and black media because my wife has to go on at six o'clock."
Charlamagne invited Biden back to the show, saying he had more questions ahead of the election.
"You've got more questions?" Biden replied. "Well, I tell you what, if you have a problem figuring out whether you're for me or Trump, then you ain't black."
Biden called his record on racial issues "second to none".
He and Charlamagne agreed he would come back on the show another time.
US Senator Tim Scott, who is black, said Biden's comments were "arrogant and demeaning" and "negative race-baiting rhetoric".
Biden adviser Symone Sanders said in a tweet the remarks were made in jest.
"He was making the distinction that he would put his record with the African American community up against Trump's any day. Period," she said.
