Kamala Harris's campaign branded Donald Trump "scared" Saturday after he proposed changing the debate schedule, as the Republican rallied in Georgia seeking to blunt the vice president's surging momentum in her bid to become America's first woman president.

In an overnight post on his Truth Social platform, Trump said he was willing to debate Harris on the conservative-leaning Fox News network on Sept. 4, while declining to participate in a previously scheduled debate on ABC.

Trump pitched the idea before going to a rally in Atlanta, where he gathered supporters in the same arena where Harris addressed an excited crowd of some 10,000 on Tuesday.