Civil rights groups called on President-elect Donald J. Trump on Monday to publicly condemn extremist movements that are espousing racism in his name after hundreds of white nationalist sympathizers spent the weekend in Washington debating ways to preserve white culture.

Mr. Trump has been accused of fanning the flames of hate groups with his hard- line positions on immigration, his hesitance to denounce the former Klansman David Duke and his occasional promotion of white nationalist accounts on Twitter. While Mr. Trump has called for an end to hate crimes and said he wants to bring the country together, he has not been full throated on expressing disapproval of the alt-right, a rebranded white nationalist movement.

“We would like him to stand up and denounce these folks,” Heidi Beirich, who tracks hate groups for the Southern Poverty Law Center, said of Mr. Trump.

“It’s inexplicable. The longer it goes on, the more you have to wonder if it’s not intentional.”

The conference, held at a federal building named after Ronald Reagan, drew about 275 attendees from around the country and attracted droves of “anti-fascist” protesters. Speakers preached the virtues of a white “ethno-state,” railed against Jews and lauded Mr. Trump’s election as a victory with Nazi salutes.

Jonathan Greenblatt, the national director of the Anti-Defamation League, said that Mr. Trump should not be blamed for every hate group that invoked his name, but that he should be doing more to discredit people using his election to make prejudice mainstream.

“To have a group like this convening steps away from the White House proclaiming that what happened two weeks ago was a great victory for them and their ideas, there is value for the president-elect stating clearly that these are not American values, that their ideology is in conflict with American ideals,” Mr. Greenblatt said. After Hillary Clinton gave a major address attacking the alt-right over the summer, Mr. Trump said that he had never heard of the movement and that “nobody even knows what it is.”
On Monday, Hope Hicks, a spokeswoman for Mr. Trump, said the president-elect disapproved of all hate groups.

“Mr. Trump has always denounced these groups and individuals associated with a message of hate,” Ms. Hicks said. “Mr. Trump will be a president for all Americans. However, he totally disavows the support of this group, which he does not want or need.”

But white nationalists showed no sign of being ready to abandon Mr. Trump.

Richard B. Spencer, the head of the National Policy Institute, which sponsored the weekend conference, said that Mr. Trump’s win had lifted the spirits of what he described as a “radical” movement and that he hoped to ride the enthusiasm by pitching policy papers on subjects such as foreign policy and immigration to the administration.

“My goal for the next five years is professionalization,” said Mr. Spencer, who has become the face of the alt-right. “That is the next step for the alt-right.”

But the conference demonstrated how far the group remained from the political mainstream and the challenges it faced explaining to the public that a desire for a white state was different from blatant racism.

As the conference concluded, Mr. Spencer shouted “Hail our people!” and “Hail victory!” — the English translation of the Nazi exhortation “Sieg heil!” Some members of the crowd shouted back and raised their arms in Nazi salutes. Asked on Monday about the comments,

Mr. Spencer said he had gotten caught up in his passion for the alt-right cause.

“My talk certainly was strident, and it definitely was about getting a rise out of people and expressing excitement,” he said. “There’s a lot of cheekiness going on and exuberance.”

Of the salute that is synonymous with anti-Semitism, he said, “That was a rhetorical flourish.”