Former President Donald Trump is struggling with an attack...

Former President Donald Trump is struggling with an attack strategy against Kamala Harris, amid reports he called her a “b**ch” repeatedly in private as the Republican presidential nominee also sees support in the polls plunge.

Two sources told The New York Times that they heard the former president make the remark on different occasions.

A spokesman for Mr Trump has since refuted the claims, with Steven Cheung denying the former president had ever used the insult to refer to Ms Harris.

“That is not language President Trump has used to describe Kamala, and it’s not how the campaign would characterise her,” he told the publication.

The newspaper also claimed Mr Trump had been trialling a number of insulting nicknames for his rival such as “Laffin’ Kamala” to mock her laugh and “Crazy Kamala”.

Meanwhile, Mr Trump has come under fire for comments he made in which he claimed he “didn’t know” his presidential rival Ms Harris was black and that she “turned black” only recently.

Former US President and Republican presidential candidate Donald Trump speaks during an election campaign rally in Bozeman, Montana. Picture: Natalie Behring/AFP

But the New York Times has painted a picture of a frustrated and lost Mr Trump since Ms Harris entered the contest.

It was reported he had lashed out at some of his closest allies, including a group pouring nearly $US18 million a week into advertisements, in three key battleground states.

According to sources who spoke to the publication on the condition of anonymity, Mr Trump is struggling as the Democrats dominate the new cycles – at a time his path to certain victory was up-ended when Mr Biden stepped down.

Trump losing control....he'll be stronger for the beating and come back bigger stronger and quicker in 2028...it will come around quick...

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