Donald Trump has proposed that the next US presidential debate take place on Fox News on September 4.

Republican presidential nominee Donald Trump has proposed to debate Democratic US Vice President Kamala Harris on Fox News on September 4, and the Harris campaign responded saying Trump is trying to back out of a debate that had been set to run on ABC.

The rules would be similar to the first debate with President Joe Biden, who has since dropped his re-election bid, Trump said in a post on Truth Social late on Friday. But this time it would have a “full arena audience” and take place in the battleground state of Pennsylvania, Trump said.

“Donald Trump is running scared and trying to back out of the debate he already agreed to and running straight to Fox News to bail him out,” the Harris campaign communications director Michael Tyler said in a statement on Saturday.

“He needs to stop playing games and show up to the debate he already committed to on Sept 10.”

Trump’s proposal for the debate on Fox came soon after the Democratic National Committee launched an advertising campaign on Friday taunting him by saying “the convicted felon is afraid to debate” and questioned whether that is due to his stance on abortion.

“The Vice President will be there one way or the other to take the opportunity to speak to a prime time national audience,” Tyler said, apparently suggesting she would show up if Trump does not.

“We’re happy to discuss further debates after the one both campaigns have already agreed to.”

After Biden dropped out of the race on July 21 and backed Harris, Trump said he would not debate her because she was not the official candidate.

On Friday, Harris, 59, secured the delegate votes needed to clinch the Democratic nomination.

Harris also said last month that she was “ready” after Fox News proposed the presidential debate between the two candidates on September 17.

Recent polls show a tight contest between Harris and Trump, who had enjoyed a bigger lead over Biden after the first debate.