Donald Trump has renewed his vow to stop radical terror groups and appeared to suggest he could move ahead with his campaign pledge to temporarily ban Muslim immigrants from coming to the US.
He proposed the Muslim ban during the Republican primary campaign, drawing sharp criticism from both parties.
During the general election, he shifted his rhetoric to focus on temporarily halting immigration from an unspecified list of countries with ties to terrorism.
Asked on Wednesday whether the deadly truck attack on a Christmas market in Berlin would make him pursue the proposed ban or a possible registry of Muslims in the US, he said: "You know my plans. All along, I've been proven to be right, 100% correct."
Meanwhile, the federal government has allowed four groups at the forefront of the white nationalist movement to register as charities and raise more than 7.8 million dollars (£6.3 million) in tax-deductible donations over the past decade, according to an Associated Press review.
Emboldened by Mr Trump's popularity, group leaders say they hope the president-elect's victory helps them raise more money and give them a larger platform for spreading their ideology.
With benevolent-sounding names such as the National Policy Institute and New Century Foundation, the tax-exempt groups present themselves as educational organisations and use donors' money to pay for websites, books and conferences to further their ideology. The money also has personally compensated leaders of the four groups.
New Century Foundation head Jared Taylor said his group raises money for the benefit of the "white race", a mission taxpayers are indirectly supporting with the group's status as a non-profit. The IRS recognised it, the Charles Martel Society, the National Policy Institute and VDare Foundation as charities more than a decade ago.
Samuel Brunson, a tax law professor at Loyola University in Chicago, said the non-profit status gives these groups a veneer of legitimacy and respectability.
"It should make people uncomfortable that the government is subsidising groups that espouse values that are incompatible with most Americans," he said.
The IRS has tried to weed out non-profit applicants that merely spread propaganda. In 1978, the agency refused to grant tax-exempt status to the National Alliance, a neo-Nazi group that published an anti-Semitic newsletter, and in 1994, a court upheld the denial of tax-exempt status for the Nationalist Movement, a Mississippi-based white nationalist group.
New Century Foundation, a Virginia-based non-profit, has raised more than 2 million dollars since 2007 and operates the American Renaissance online magazine, which touts a philosophy that it's "entirely normal" for whites to want to be a majority race.
Mr Taylor, a Yale-educated, self-described "race realist", said his group, founded in 1994, abides by all laws governing non-profits.
"We certainly did not conceal our intentions," he said. "I think we are educational in precisely the terms that Congress defined."
"We hold it (the money) in trust for the white race. We take this seriously. This is not something we do for fun or profit. This is our duty to our people."
The Montana-based National Policy Institute is run by Richard Spencer, who popularised the term alternative right about a decade ago. The so-called alt-right is a fringe movement that has been described as a mix of racism, white nationalism and populism.
Mr Spencer's group raised 442,482 dollars in tax-deductible contributions from 2007 through to 2012. More recent fundraising figures for the group are not available in online tax returns, but Mr Spencer said Mr Trump's candidacy has boosted his group's fundraising.
Mr Spencer hosted a post-election conference in Washington that ended with audience members mimicking Nazi salutes after he shouted: "Hail Trump, hail our people, hail victory!"
Mr Spencer has advocated for an "ethno-state" that would be a "safe space" for white people.
The Georgia-based Charles Martel Society was founded by wealthy publisher William H Regnery II, who also founded the National Policy Institute.
The group raised 568,526 dollars between 2007 and 2014 and publishes the Occidental Quarterly. In an article last December, the journal's editor applauded Mr Trump's campaign as a "game changer" for white people who oppose immigration and multiculturalism, but said they "have a long way to go to really change the public discussion of race, Western culture, and Jewish influence".
The Connecticut-based VDare Foundation is led by Peter Brimelow, founder and editor of an anti-immigration website. Mr Brimelow, who spoke at the National Policy Institute's conference last month, founded his non-profit in 1999 and raised nearly 4.8 million dollars between 2007 and 2015.
He has denied that his website is white nationalist but acknowledged it publishes works by writers who fit that description "in the sense that they aim to defend the interests of American whites".