Donald Trump has spent the past week talking up his efforts to attract African-American voters.

On Thursday, the Clinton campaign revealed its response: A one-minute video making the case that Donald Trump remains the candidate of choice for white supremacists and neo-Nazis.

The montage features leaders of the Ku Klux Klan and other white nationalist groups offering resounding endorsements to the New York businessman, whom Hillary Clinton accused of “taking a hate movement mainstream”.

“The reason a lot of Klan members like Donald Trump is because a lot of what he believes, we believe in,” said a robed Imperial Wizard of the Rebel Brigade of the Knights of the KKK.

The advert comes the same day Ms Clinton is expected to address the so-called “alt-right” movement, and a day after Mr Trump labeled her a “bigot” in his latest appeal to black and Latino voters.

Donald Trump calls Hillary Clinton a 'bigot'

Former KKK Grand Wizard David Duke – who recently announced his run for US Senate – can be heard in the video pleading the case for Mr Trump’s election.

“Voting against Donald Trump at this point is really treason to your heritage,” he said.

The video provoked a hostile response from the Trump campaign.

"Hillary Clinton and her campaign went to a disgusting new low today as they released a video tying the Trump campaign with horrific racial images," said Pastor Mark Burns, calling the ad "repulsive" and "revolting".

He added: "I call on Hillary Clinton to disavow this video and her campaign for this sickening act that has no place in our world."

Mr Trump has struggled to distance himself from white nationalist groups, whose members have praised him in online messages and turned up at his rallies.

America unmasked: The images that reveal the Ku Klux Klan is alive and kicking Show all 11 1 /11 America unmasked: The images that reveal the Ku Klux Klan is alive and kicking America unmasked: The images that reveal the Ku Klux Klan is alive and kicking Klan members gather at a cross 'lighting' in Scottsboro, Alabama America unmasked: The images that reveal the Ku Klux Klan is alive and kicking An Imperial Knighthawk of the Brotherhood of the Klans America unmasked: The images that reveal the Ku Klux Klan is alive and kicking A KKK wedding ceremony in Walker, Louisiana America unmasked: The images that reveal the Ku Klux Klan is alive and kicking Children at a Klu Klux Klan 'spring unity' gathering America unmasked: The images that reveal the Ku Klux Klan is alive and kicking A member of the Supreme White Alliance makes sure everyone gets the message America unmasked: The images that reveal the Ku Klux Klan is alive and kicking A confrontation takes place in Tupelo, Mississippi America unmasked: The images that reveal the Ku Klux Klan is alive and kicking A member of the Imperial Klans of America shows off his tattoos during the annual three-day Nordic Fest held in Kentucky America unmasked: The images that reveal the Ku Klux Klan is alive and kicking The skinhead group Totenkopf Saints perform at the Nordic Fest America unmasked: The images that reveal the Ku Klux Klan is alive and kicking Proposed Klansmen line up during a 'naturalisation' ceremony, in which they become citizens of the 'Invisible Empire' America unmasked: The images that reveal the Ku Klux Klan is alive and kicking A child has his outfit adjusted at a Labor Day rally in Arkansas America unmasked: The images that reveal the Ku Klux Klan is alive and kicking Ms Ruth makes an outfit for the Exalted Cyclops

Mr Trump has stopped short of denouncing their support even in the face of intense condemnation.

When asked by CNN’s Jake Tapper whether he would reject the support of Mr Duke, for example, Mr Trump pleaded ignorance.

“I know nothing about David Duke,” he said in the 28 February interview. “I know nothing about white supremacists. And so you’re asking me a question that I’m supposed to be talking about people that I know nothing about.”

The Trump campaign has recently drawn significant criticism for the hiring of Breitbart executive chairman Stephen Bannon to run his campaign following the resignation of Paul Manafort.

Under the watch of Mr Bannon, conservative news site Breitbart.com has become a favourite of white nationalist readers, according to a Twitter analysis by The Investigative Fund.

Although Mr Bannon embraces the appeal of Breitbart to “alt-right” contingents – which includes white nationalist, anti-Islamic, and anti-immigrant types – he attributed the love of the site by racists to a “certain element” of their movement.

“Look, are there some people that are white nationalists that are attracted to some of the philosophies of the alt-right? Maybe,” he said. “Are there some people that are anti-Semitic that are attracted? Maybe. ... Maybe some people are attracted to the alt-right that are homophobes, right?