"She [Harris] was extraordinarily nasty to Kavanaugh ... she was nasty to a level that was just a horrible thing, the way she treated now-Justice Kavanaugh, and I won't forget that soon," Trump said during a news conference, referring to Associate Justice of the Supreme Court Brett Kavanaugh, who was accused in 2018 of sexual assault.
"I think she was the meanest," Trump added, also noting that Harris "did very poorly in the primaries."
"She's a big tax raiser, she's a big slasher of funds for our military ... she was probably nastier than even Pocahontas to Joe Biden [during the presidential debates]," Trump also stated, using an offensive name to refer to Senator Elizabeth Warren (D-MA).
"It's hard to pick someone that disrespectful - she said things during the debates, the Democratic primary debates that were horrible about 'sleepy Joe,'" the president continued.
"I like Vice President Mike Pence much better," Trump responded when asked by reporters if he thought Harris would help or hurt Biden's chances at a presidential victory.
Biden on Tuesday announced that he chose Harris as his running mate because she is a "fearless fighter" and "one of the country's finest public servants."
"I need someone working alongside me who is smart, tough, and ready to lead. Kamala is that person. I need someone who understands the pain that so many people in our nation are suffering. Whether they've lost their job, their business, a loved one to this virus," Biden said about his choice, Axios reported.
Harris dropped out of the 2020 presidential race in December after attempting to become the first Black woman to win a major party's presidential nomination. Harris, the daughter of immigrants, has been very vocal on racial justice issues, as well as matters like corruption, women's rights and election interference.