Donald Trump has attracted a following from white supremacist group Ku Klux Klan, who appeared in long cloaks and head-coverings at the Nevada caucus.

Mr Trump has “refused” to condemn those who believe Christian white people are a superior race, and has “encouraged” the hatred, according to Occupy Democrats.

Multiple white nationalists have found appeal in Trump’s message and have aligned their support with the presidential candidate.

The latest is David Duke, a former Ku Klux Klan grand wizard, who called for listeners of his radio show to support Trump and volunteer for his campaign.

Duke’s comments came the same day that a white nationalist super PAC announced it made calls to every consumer landline in Vermont in support of Trump. The group also supported Trump in Iowa.

A national survey last month found nearly 20 per cent of Trump’s supporters disagreed with the Emancipation Proclamation, which freed Southern slaves during the Civil War, The New York Times reported this week.

Trump has fanned flames of racism with his talk of banning Muslims from the US and building a wall along the US border to keep out Mexicans.