The New York-based advocacy group’s data showed 5,125 cases reported in 2020, compared to 2,724 in 2019, even though incidents on college campuses dropped by more than half, possibly due to Covid-19 restrictions.

Critics say white supremacism got a boost from US President Donald Trump’s recently-ended presidency though he denied racism and said he was smeared by political opponents.

His successor, President Joe Biden, has ordered an assessment of the risk of domestic terrorism in the wake of the Jan 6 attack on the US Capitol by Trump supporters, some of whom displayed supremacist symbols.

The ADL said in a report on its website that supremacist propaganda appeared in every US state except Hawaii last year, with the highest levels of activity in Texas, Washington, California, New Jersey, New York, Massachusetts, Virginia and Pennsylvania.

“The barrage of propaganda, which overwhelmingly features veiled white supremacist language with a patriotic slant, is an effort to normalise white supremacists’ message and bolster recruitment efforts while targeting minority groups including Jews, blacks, Muslims, non-white immigrants, and the LGBTQ community,” it said.

UN Secretary-General Antonio Guterres warned last month that white supremacy and neo-Nazi movements were becoming a “transnational threat” and had exploited the coronavirus pandemic to boost their support.

US Representative Jackie Speier sent a letter earlier this year to Biden urging him to issue an executive order identifying white supremacy and violent extremism as a threat to national security.