The OK hand sign has officially been labelled a white supremacist "hate symbol" by US anti-bigotry organisation the Anti-Defamation League.

The ADL, headed by former Obama White House official Jonathan Greenblatt, announced on Thursday it had updated its "Hate on Display" online database to include 36 new entries including white supremacist symbols adopted in recent years by the alt-right.

The additions include the OK sign — which started as a hoax by users of online messageboard 4chan — the phrase "It's Okay to Be White", the "Dylann Roof Bowlcut", the "Moon Man" and the "Happy Merchant".

"Even as extremists continue to use symbols that may be years or decades old, they regularly create new symbols, memes and slogans to express their hateful sentiments," Mr Greenblatt said in a statement.

"We believe law enforcement and the public needs to be fully informed about the meaning of these images, which can serve as a first warning sign to the presence of haters in a community or school."

The ADL said a number of the new symbols had appeared at white supremacist events and also frequently appear online in venues such as 4chan, 8chan and Reddit, the ADL said, and have also spread into other more popular mainstream platforms such as Twitter, Facebook and gaming platforms.

A July survey by the ADL found 23 per cent of online gamers had been "exposed to white supremacist ideology while gaming". "These are the latest calling cards of hate," ADL senior fellow Mark Pitcavage said in a statement.

"While some hate symbols are short-lived, others take on a life of their own and become tools for online trolling. We pay special attention to those symbols that exhibit staying power as well as those that move from online usage into the real world."

The ADL said some of the slogans, such as the phrase, "It's Okay to be White", had recently appeared in white supremacist flyering campaigns on and off university campuses. The group said it documented 313 cases of white supremacist propaganda on campuses in 2018-19, a 7 per cent increase on the prior year.

NEWLY ADDED HATE SYMBOLS

• The "OK" hand symbol: Begun as a hoax by members of the website 4chan, the OK symbol became a popular trolling tactic. By 2019, the symbol was being used in some circles as a sincere expression of white supremacy.
• Burning neo-Nazi symbols: Neo-Nazis have adopted the Ku Klux Klan practice of symbolic burnings, substituting swastikas and other neo-Nazi symbols such as othala and life runes, for crosses.
• Dylann Roof's "Bowlcut": The "Bowlcut" is an image of a bowl-shaped haircut resembling the one worn by white supremacist mass killer Dylann Roof. Those who use the bowlcut image or other "bowl" references admire Roof and call for others to emulate his 2015 mass shooting attack at Emanuel AME Church in Charleston, South Carolina.
• Happy Merchant: An anti-Semitic meme depicting a drawing of a Jewish man with heavily stereotyped facial features who is greedily rubbing his hands together. The meme is by far the most popular anti-Semitic meme among white supremacists.
• "Anudda Shoah": An anti-Semitic phrase that first became popular among white supremacists in 2014 to mock Jews, whom they claim bring up the Holocaust ("Shoah" is the Hebrew term for Holocaust) when confronted with anything they don't like.
• Diversity = White Genocide: A white supremacist slogan intended to suggest multiculturalism will mean the demise of the white race.