The move came in connection with a press conference on Thursday, where Trump proposed election debates on TV channels NBC, ABC, and Fox.
ABC has confirmed that the candidates have agreed on a debate on the channel on September 10, but it is unclear whether Harris has accepted participation in the two others.
I'm looking forward to the debates because I think we need to clarify things, said Trump.
The press conference at Trump's residence Mar-a-Lago in Florida is the first public appearance the former president makes since Harris announced her vice presidential candidate Tim Walz earlier in the week.
At the same time, Trump's own vice presidential candidate J D Vance has been struggling with lukewarm opinion polls during his first weeks as Trump's running mate.
He's doing a good job, said Trump about his vice presidential candidate.
Trump has previously stated that vice presidential candidates rarely affect the outcome of elections, but opened up for a TV-broadcast debate between Vance and Walz on CBS during the press conference.
