They are young, Internet-savvy and advocates of "white identity".

Dubbed the Alternative Right, or Alt-Right, this group of Americans is spreading its hateful brand of conservatism through chat groups and social media, and has become a major source of concern in the United States.

The movement has been linked to Republican presidential nominee Donald Trump's campaign and was singled out by the Democratic Party's nominee, Mrs Hillary Clinton, in a speech in Nevada last Thursday.

Quoting the Wall Street Journal, Mrs Clinton defined the group as a loosely organised movement, mostly online, that "rejects mainstream conservatism, promotes nationalism and views immigration and multiculturalism as threats to white identity".

"Of course there's always been a paranoid fringe in our politics, steeped in racial resentment," she said. "But it's never had the nominee of a major party stoking it, encouraging it, and giving it a national megaphone. Until now."

The term Alternative Right was coined in 2008 by Mr Richard Bertrand Spencer, who heads the think-tank National Policy Institute, "an independent organisation dedicated to the heritage, identity and future of people of European descent in the United States and around the world", according to its website.

The Southern Poverty Law Centre (SPLC), which tracks hate groups, says the term refers to "a set of far- right ideologies, groups and individuals whose core belief is that 'white identity' is under attack by multicultural forces using 'political correctness' and 'social justice' to undermine white people and 'their' civilisation".

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The movement mainly exists on social media such as Twitter, where advocates use the hashtag #AltRight, or on online message boards like 4chan. Advocates shun establishment conservatives, mocking them for their moderate positions on race and immigration.

"They are a coterie of anti- Semites, Muslim bashers, anti-black racists and nativists," said Mr Nathan Lean, author of The Islamophobia Industry, who added that rather than being politically organised, they came out of the woodwork following Mr Trump's inflammatory statements about minorities.

Some notable individuals associated with the group include Mr Peter Thiel, co-founder of PayPal, who was also a Trump delegate at the Republican National Convention; and Mr Stephen Bannon, head of a right-wing website called Breitbart.com, who became Mr Trump's campaign chief executive on Aug 17.

Ms Heidi Beirich, an expert on the white supremacist movement from the SPLC, said in a statement that "Breitbart News consistently provides a platform for extremist voices, most notably anti-immigrant and anti-Muslim figures", and has, since 2015, also championed racist rhetoric of the Alt-Right.

She added that with Mr Bannon's appointment to the Trump campaign, "the line between Trump and the extreme right has just gone from fuzzy to virtually non-existent".

While Alt-Right members have capitalised on Mrs Clinton's speech to further their cause, experts believe it was important for her to draw attention to "an ugly strain of racism and xenophobia".

Mr Lean said: "She's drawing a clear moral line in the sand by referencing the KKK, white nationalists and other extreme figures, and is essentially saying there are two choices in this election: the extremists and those who reject extremism."

While the group is likely to give Mr Trump a fair showing at the polls, Mr Lean said "the real concern is how, as a result of their emergence in this election, they have positioned themselves to become a more mainstream part of the Republican Party moving forward".

Also expressing concern for the future, Mrs Clinton added: "From the start, Donald Trump has built his campaign on prejudice and paranoia. He's taking hate groups mainstream and helping a radical fringe take over one of America's two major political parties. His disregard for the values that make our country great is profoundly dangerous."