Richard Spencer, a white nationalist, was kicked out of the hotel where the Conservative Political Action Conference is taking place, a CPAC spokesman confirmed to NPR.
Spencer was spotted in the lobby of the Gaylord National Resort outside Washington, D.C., talking with reporters. That's when CPAC officials were alerted to Spencer's presence.
"His views are repugnant and have absolutely nothing to do with conservatism or what we do here," said CPAC spokesman Ian Walters.
Spencer purchased a general admission pass Thursday morning, Walters said.
"He's anti-free markets, anti-Constitution, anti-pluralism," Walters added. "This was one bad egg who bought a ticket."
He described the alt-right and Spencer's views as "vile," "venomous," "horrible" and "repulsive."
CPAC is trying to send a message that it wants nothing to do with the so-called alt-right, a white nationalist movement that latched on to Donald Trump's rise. The president's chief strategist in the White House, Steve Bannon, ran Breitbart, which he called a "platform for the alt-right." Bannon and White House Chief of Staff Reince Priebus are speaking at CPAC Thursday afternoon.
CPAC also invited then disinvited Milo Yiannopoulos, a former Breitbart editor with controversial views, after video surfaced of him seeming to endorse pedophilia.
Dan Schneider, executive director of the American Conservative Union, which runs CPAC, spoke out forcefully against the alt-right at an earlier event.
"CPAC, we have been slapped in the face," Schneider said. "There is a sinister organization that is trying to worm its way in, into our ranks."
The alt-right, which "had been used for a long time in a very good and normal way," had been "hijacked [by a] hate-filled, left-wing fascist group," Schneider said. "We must not allow them to be normalized. They are not part of us."
Walters noted, "It's not even close to even being somewhat representative of what goes on here. And everyone here is in agreement."
He noted that Schneider's speech was a deliberate addition to a four-part series of speeches here on conservatism.
A previous version of this story incorrectly spelled Milo Yiannopoulos' last name as Yiannopolous.