A group of protesters describing themselves as nationalists interrupted an author's book talk with chants of "This land is our land" at the popular Politics and Prose bookstore in Northwest Washington on Saturday.

The incident at Politics and Prose, an independent bookstore and local staple in the Chevy Chase neighborhood of D.C. happened Saturday afternoon according to the author, Jonathan M. Metzl, and filmmaker Catherine Wigginton, who was present during the interruption.

The men walked in and chanted "This land is our land" as Metzl, the director of the Center for Medicine, Health and Society at Vanderbilt University, was speaking about his new book, "Dying of Whiteness: How the Politics of Racial Resentment is Killing America's Heartland."

"The crowd didn't really know what to make of it. Everybody thought it was a joke at first," Metzl told News4.

Video posted on Twitter shows the group of about 10 men led by one person holding a loudspeaker while talking about white, working-class people, and identified themselves as "nationalists" and "identitarians."

Metzl said he had just recognized a man in the audience who had helped his father and grandparents escape Nazi Austria by offering to be their host family.

"Not five minutes before, I had acknowledged him and said this is how great America can be when it is bold and generous," Metzl said.

Then, he saw the group come into the bookstore.

"All of a sudden I saw these guys very boldly walking, almost in formation," Metzl said.

So this bullshit just went down today at Politics & Prose. White nationalists disrupting @JonathanMetzl talk on his book Dying of Whiteness. Point made. @PM_Learn pic.twitter.com/nucKlrJ8X2 — Catherine Wigginton (@cewigginton) April 27, 2019

The man with a megaphone leading the group then began shouting as the crowd booed him.

“You would have the white working class trade their homeland for handouts," the man said. "But we, as nationalists, and identitarians, can offer the workers of this country, a homeland, our birthright, in addition to health care, good jobs and so forth."

The group chanted "this land is our land," before leaving the building.

The whole interaction did not last for more than five minutes said filmmaker Catherine Wigginton, who said she stepped into the store after seeing the men approaching from along Connecticut Avenue.

"As I was standing outside I saw them march up," Wigginton told News4. "The whole thing was very fast."

She had been in the area as part of the same conference that brought Metzl to Politics and Prose, the Antiracist Book Festival at American University, where she was promoting her film "I'm not Racist...Am I?"

Wigginton and Metzl both said they were struck by the boldness of this demonstration on the same day as a shooting at a synagogue in Southern California.

"The scary part is these [people] are very emboldened right now. It was the intensity of it," Metzl said.

D.C. Mayor Muriel Bowser condemned the incident in a series of tweets that also condemned the shooting at Chabad of Poway synagogue in the town of Poway, California.

"Between the horrific act of hate and antisemitism at Chabad of Poway and the ignorance and hate from the white nationalists who interrupted a book talk today in DC, my heart is broken," Bowser said.

After the group exited, Metzl said he paused before asking the audience to reflect and process the moment.

"This was amazing," Wigginton said. "He led and opened the space up for conversation afterwards."