Clinton used unusually tough language during her speech in Reno, Nevada, detailing a history of what she said were Trump's discriminatory actions, including the fact that he had been sued as a young developer for failing to rent to black and Latino tenants.

She added that Trump's recent choice of Steven Bannion (pictured below), a hardline conservative, as his new campaign chief showed he had embraced extremist white nationalist stances associated with the "alt-right" movement.

Clinton released a video on Thursday ahead of her Nevada speech tying Trump to white supremacist groups. The video shows a Ku Klux Klan member praising Trump and plays a recording of former leader Klan leader David Duke calling on white people to vote for Trump.

Trump's campaign called for the Clinton campaign to withdraw the video. "This type of rhetoric and repulsive advertising is revolting and completely beyond the pale," Mark Burns, an African-American pastor who supports Trump, said in a statement.

Dark conspiracy theories

"A man with a long history of racial discrimination who traffics in dark conspiracy theories drawn from the pages of supermarket tabloids and the far dark reaches of the internet should never run our government or command our military," Clinton said. "Donald Trump has built his campaign on prejudice and paranoia," she said. "He's taking hate groups mainstream and helping a radical fringe take over the Republican Party.

"His disregard for the values that make our country great is profoundly dangerous.

"This is a moment of reckoning for every Republican dismayed that the Party of Lincoln has become the Party of Trump," Clinton said, referring to Abraham Lincoln, the first Republican president, who issued the Emancipation Proclamation and championed the 13th Amendment to the US Constitution during the Civil War that led to the abolition of slavery in 1865.

Clinton set for White House?

A survey by Quinnipiac University gave Clinton a 51 to 41 percent lead over Trump in a head-to-head race. Clinton needs to retain support from black and Latino voters to win the November 8 election, the same coalition that helped propel Democrat Barack Obama to the White House in 2008.

A Reuters/Ipsos States of the Nation poll for the week beginning Aug. 15 found Clinton beating Trump among Hispanic voters by 15 percentage points, and by 57 percentage points among black voters.

Trump changes tack

Trump recently sought - belatedly - to enlarge his tiny base of support among black voters, arguing that African-Americans have "nothing to lose" by voting for him.

Speaking in New Hampshire later on Thursday, the real estate mogul attacked Clinton, saying she was accusing "the decent Americans who support this campaign, your campaign, of being racists, which we're not."

"To Hillary Clinton, and to her donors and advisers, pushing her to spread smears and her lies about decent people, I have three words ... shame on you."

Calling it "a tired, disgusting argument," he said it was Clinton who was being a "racist" by viewing minorities merely as a source of votes while doing nothing for them. At a Mississippi rally on Wednesday, Trump called Clinton a "bigot who sees people of color only as votes, not as human beings."

Trump has started to moderate his earlier comments on immigration, saying he would focus on deporting the "bad" immigrants without uprooting the "good" ones, a shift from his early insistence that all undocumented immigrants would be deported.

However, he reiterated on Thursday that he would build a wall on the southern border and make Mexico pay for it.

jbh/kl (AFP, Reuters)