CNN  — 

President Donald Trump called Joe Biden “weak” and said he is not worried about a potential challenge from the former vice president in the 2020 presidential race, during a phone interview with Fox News’ Jeanine Pirro Saturday night.

Biden, who served as a senator before becoming vice president for President Barack Obama, is one of many Democrats eyeing a presidential run in 2020. While he has not officially announced his candidacy, Biden has been vocal about his qualifications.

“I think I’m the most qualified person in the country to be president,” Biden said during a book tour event at the University of Montana in December. “The issues that we face as a country today are the issues that have been in my wheelhouse, that I’ve worked on my whole life.”

Trump mocked Biden as a “1-percenter,” in the interview with Pirro.

“He ran two or three times, he never got above 1%,” Trump said. “And then, Obama came along and took him off the trash heap, and he became the vice president.”

“He’s weak. So, we’ll see what happens with him,” Trump said.

Trump also weighed in on other potential challengers in the 2020 presidential race.

Massachusetts Sen. Elizabeth Warren, Hawaii Rep. Tulsi Gabbard and former secretary of Housing and Urban Development Julian Castro all have recently announced bids.

“I’m not worried,” Trump said. “So far, I love the competition. I love what I see.”

Several other prominent Democrats haven’t officially announced plans to run but have taken steps that indicate an announcement could come soon, including building up their staffs and making trips to important primary and caucus states.

Sens. Kamala Harris, Kirsten Gillibrand, Cory Booker and Bernie Sanders; former New York Mayor Michael Bloomberg; and former Rep. Beto O’Rourke are among those who have hinted at a run.

California billionaire and frequent Trump critic Tom Steyer announced earlier this year that he would not run for president in 2020.

“A couple of them aren’t running that I was hoping were going to run,” Trump said, though he did not say to whom he was referring. “I was sort of looking forward to that.”

Trump added, “But, I’ll be watching. And, whoever it is, I think we’re going to do just fine.”

CORRECTION: This story has been updated to reflect Tom Steyer’s January announcement that he will not run for president in 2020.