Donald Trump, who during his presidential campaign has vowed to ban Muslim immigrants and erect a wall to prevent Mexican immigration, has said that he would reject bigotry "in all forms" if elected president.

"This is my pledge to the American people: as your president I will be your greatest champion," Mr Trump said in a statement posted on Facebook.

"I will fight to ensure that every American is treated equally, protected equally, and honoured equally," the Republican presidential nominee said.

"We will reject bigotry and hatred and oppression in all its forms, and seek a new future built on our common culture and values as one American people."

The pronouncement comes as something of a surprise from a candidate who until now has done little to endear himself to minorities or women.

The embattled Republican presidential nominee has made a successful campaign out of incendiary rhetoric and defying political correctness.