WASHINGTON D.C. -- A popular Italian restaurant in Washington D.C. has issued an apology, saying it unintentionally hosted a white nationalist group and the diners performed a Nazi salute while eating there.

Maggiano’s Little Italy posted an apology on its Facebook page Monday.

On Friday night, Maggiano’s in Friendship Heights was the inadvertent site of a protest that caused us to close our... Posted by Maggiano's Little Italy Chevy Chase on Monday, November 21, 2016

The restaurant said it didn’t realize it was hosting a banquet Friday for a group called the National Policy Institute, whose website says it advocates for the heritage and identity of those of European descent in the U.S.

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The post said the group made reservation at the last minute using a different name. The group was gathered in Washington for a conference and celebrated Republican Donald Trump’s election.

A tweeted photo from former reality star Tila Tequila appeared to show people making a Nazi salute. Her account later seemed to have been suspended.

Photo posted to Twitter appeared to show people making the Nazi salute. Tila Tequila (@AngelTilaLove)

Maggiano’s said it has donated its profits from the evening to the Anti-Defamation League.

The far right-wing group known as the alt-right latched onto to the Trump campaign -- and some of its leaders say his victory has given them a big boost.

“Hail Trump, hail our people, hail victory,” was heard over the weekend at a meeting in Washington, D.C.

A meeting of the National Policy Institute drew hundreds to the Ronald Reagan pavilion in Washington, CBS News correspondent Jericka Duncan reported.

Since 2008, the alt- or alternative-right movement lived mostly on obscure message boards online. It gained more attention after Trump hired Steve Bannon to run his presidential campaign in August.

Bannon’s Breitbart website is, among other things, seen as the largest platform for the alt-right message -- with more than 300 million views in the last month.

Thirty-eight-year old Richard Spencer, who is president of the National Policy Institute, said he is enthusiastic about Bannon acting as the strategist for President-elect Donald Trump.

Richard Spencer. CBS News

“Because Breitbart has been an open place for a lot of ideas that I care about,” he said.

Bannon denies being alt-right.

Its members are usually college-educated white males, with strong right-wing views. They are difficult to define because of the wide range of members – from those who believe that America will be great only when it looks out for itself, to those who believe in anti-immigration and white dominance.

“They say instead of asking what’s good for the world they ask what is good for us,” explained Professor Thomas Main, a public policy professor at Baruch College in New York City. He has been following the movement for years.

He said after the Great Recession, and with the country’s increasing minority population, many white men began to feel left out of the political process.

“I think what happened is that all of those shocks to the system, in a lot of people, especially on the right say, ‘gee our current way of thinking is not working for us, we need something new,’” said Main.

What does Spencer say to people who call groups like his racist?

“The word racist doesn’t have any meaning anymore,” he said. “It’s basically calling me a mean old guy.”

Does he discriminate against people because of the color of their skin?

“Everyone is discriminating in all sorts of things in terms of life,” he said. “I discriminate all the time – discriminating is living.”

Spencer said he opposes violence. He calls the election of Trump a step toward our new normal.