Donald Trump on Saturday rejected another debate with Vice-President Kamala Harris before the U.S. presidential election, hours after the Democratic candidate's campaign said she had agreed to an Oct. 23 matchup with her Republican rival on CNN.

"Vice-President Harris is ready for another opportunity to share a stage with Donald Trump, and she has accepted CNN's invitation to a debate on Oct. 23. Donald Trump should have no problem agreeing to this debate," Jen O'Malley Dillon, the chair of the Harris campaign, said in a statement.

Trump stuck to his previous position that there would not be another debate before voters go to the polls in the Nov. 5 election.

"The problem with another debate is that it's just too late. Voting has already started," the former U.S. president told supporters at a rally in Wilmington, N.C.

Harris and Trump debated each other for the first time on Sept. 10, in a contest that polls showed she won.

Trump debated President Joe Biden in June.

Biden's shaky performance in that debate rattled Democrats and prompted strategists to ask whether their party should take the unprecedented step of replacing the 81-year-old president as their candidate.

Biden withdrew from the race for the White House in July.