WASHINGTON: Donald Trump said Tuesday he had "reached an agreement" for a September 10 debate with Kamala Harris, two days after he threatened to pull out - although there was no confirmation from the US vice president that a deal had been struck.

Trump posted on his Truth Social platform that the rivals had agreed that the ABC showdown would run under the same rules as CNN's June 27 debate, with no studio audience and each candidate's microphone muted when the other is speaking.

Calling ABC "by far the nastiest and most unfair newscaster in the business," Trump said the network had given him assurances that the debate in Philadelphia would be "fair and equitable."

But the Harris campaign - which had been pushing for a clash with mics switched on throughout - responded by accusing Trump of moving the goalposts and was coy about whether it was accepting the terms.

"Both candidates have publicly made clear their willingness to debate with unmuted mics for the duration of the debate to fully allow for substantive exchanges between the candidates - but it appears Donald Trump is letting his handlers overrule him. Sad!" the Harris campaign said in a statement.

Trump has previously balked at taking part in the debate, which comes on the heels of Harris's lightning rise as the Democratic White House nominee after President Joe Biden stepped aside following his dismal showing in the CNN debate.

The Republican accused ABC of bias on Sunday, posting: "I ask, why would I do the Debate against Kamala Harris on that network?"

His campaign maintains that the debate should occur under the conditions agreed with Biden before he dropped out, although the ex-president himself has said the mic issue "doesn't matter to me. I'd rather have it probably on."

Harris's team says the Trump camp wants the mics muted to help the Republican maintain discipline when not speaking, because "they don't think their candidate can act presidential for 90 minutes."

Trump added in his latest post that Harris had declined a September 4 debate on Fox News, but pledged to keep the date open in case she "changes her mind."

 -AFP