US presidential candidate Kamala Harris dominated her Democratic rivals in a debate on Thursday, confronting front-runner Joe Biden's race record.
During an emotional exchange, Harris turned to Biden unprompted and said, "I do not believe you are a racist" but added that she had found his comments personally "hurtful".
Biden, who was on the defensive throughout the night, said she had "mischaracterised" his position, insisting he had entered politics to champion civil rights.
Nine candidates who participated in the televised debate are vying to take on Republican President Donald Trump in the 2020 election.
The Democratic candidate will be selected at the party's convention next summer.