The campaigns of Donald Trump and Kamala Harris clashed on Monday over next month’s U.S. presidential debate, with the vice president’s team seeking a return to open microphones while her Republican rival threatened to pull out entirely, suggesting the previously agreed-upon ABC network was biased.

“Why would I do the Debate against Kamala Harris on that network?” Trump, who is making his third bid for the White House, wrote in a social media post late Sunday night that also accused the network of bias. “Stay tuned!!!”

Harris spokesperson Brian Fallon said on Monday the vice president’s campaign wanted the broadcaster to keep the candidates’ microphones on throughout the event, not muted when their opponent was speaking as in the last presidential debate. So-called “hot mics” can help or hurt political candidates, catching off-hand comments that sometimes were not meant for the public.

“The Vice President is ready to deal with Trump’s constant lies and interruptions in real-time. Trump should stop hiding behind the mute button,” Fallon said in a statement.

Trump campaign senior adviser Jason Miller said in a statement they had already agreed to the same terms as CNN’s June debate, which had muted microphones, adding: “We said no changes to the agreed-upon rules.”

But Trump later told reporters that he preferred to have his microphone kept on, adding that he did not like it muted last time and that he was not preparing much for the face-off against his new rival.

“Doesn’t matter to me. I’d rather have it, probably, on. But the agreement was that it would be the same as it was last time,” Trump said.

“I’m not spending a lot of time on it. I think my whole life I’ve been preparing for a debate,” Trump added. “You can’t cram knowledge into your head, for you know, 30 years of knowledge in one week. So, you know, there’s a little debate prep, but I’ve always done it more or less the same way.”

Representatives for ABC did not immediately respond to a request for comment.

Harris secured the Democratic nomination after President Joe Biden stepped aside last month, and had said they would do the Sept. 10 debate hosted by ABC News previously agreed to by Biden and Trump.

Biden had pushed for earlier debates, hoping to boost his campaign and cast a brighter light on Trump. But his own halting performance at the June 27 face-off triggered alarm within his party, with him ending his reelection bid weeks later.

Trump had floated another debate hosted by Fox News on Sept. 4, which he later said would be a televised town hall with just himself and host Sean Hannity. The Harris campaign said no.

The vice presidential candidates, Republican U.S. Senator JD Vance and Democratic Minnesota Governor Tim Walz, are scheduled to debate Oct. 1 on CBS News.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)