At least 1,000 Jews, immigrants, and activists protested outside Immigration and Customs Enforcement’s Washington, D.C., headquarters on Tuesday afternoon, shutting down all points of entry for several hours.

“Never again means close the camps,” the protesters chanted in sweltering, 95-degree heat, as they stood together with linked arms outside the doors of the building. They hung an enormous banner over the entry ramp to ICE headquarters that read, “Pelosi, Never Again Is Now.”

The demonstrators, several of whom were arrested Tuesday afternoon, were part of an event organized by Never Again Action, a Jewish activist group that’s been protesting outside ICE facilities around America, and Movimiento Cosecha, an organization fighting for undocumented immigrants. Their goal was to disrupt ICE’s daily work, and they surrounded the headquarters at 1 p.m., hoping to grab people getting back from lunch.

Federal workers were forced to walk around the protesters, looking for ways to enter the building, as people outside caught glimpses of workers inside checking the doors.

“We will not allow them to get to their destructive place of work,” one protester said.

Demonstrators sang in Hebrew, English, and Spanish, wearing yellow shirts that said “Never Again Para Nadie,” the latter meaning “for anyone.” Some chanted “the whole world is watching” and “quit your jobs.”

According to Movimiento Cosecha, ICE attempted to move busloads of its employees to a different facility during the protest because employees were unable to work.

Police arrested some of the protesters, although it remains unclear how many. Never Again Action posted a video of arrestees in handcuffs on its Facebook page.

“So we’re inside right now, we’re in the process of having our handcuffs changed to zip ties,” someone can be heard saying as the camera pans around the room. “And we are standing in solidarity with everyone outside. We know this is a choice for us, it’s not a choice for everyone.”

The arrestees couldn’t immediately be taken to the police station, according to reports from organizers, as protesters were blocking every exit. At one point, police on motorcycles moved toward the line of protesters with their sirens on and engines revving, but no one budged.

ICE was blockaded for five hours, and video footage showed that the agency sent its employees home early.

Sophie Ellman-Golan, a 27-year-old organizer of Tuesday’s march, told The Daily Beast the night before the D.C. protest that she hadn’t given out the location of the march ahead of time because NAA doesn’t have a protest permit. “We don’t want to make it easy for the law to find us,” she said.

NAA is a decentralized group, with 100 people filling various volunteer roles from press release writer to legal observer to medic. All that’s needed to set up an NAA group is access to the online handbook and a couple of Jews.

“In New Jersey when we marched there were cheers from cars we walked past,” said Ellman-Golan. “But oftentimes these facilities are intentionally isolated from everyone.”

Ellman-Golan led an assembly the night before the protest, where she gave people instructions for the next day, warning them what to do should the police inevitably show up. She said she was ready for the media attention, for the possible arrests, and for Jews to step up and take action.

While there’s already been a lot of talk about the acceptability of comparing the Holocaust to ICE detention camps, Never Again Action isn’t concerned about that. “Our goal was to sound the alarm to non-immigrant mainstream America,” says community organizer Alyssa Rubin, 25, who helped organize Tuesday’s march.

Rubin estimates that over 125 people have been arrested thus far in the few weeks since the group’s protests began. The New York Lawyer’s Guild has offered aid to the 100 plus people who have already been arrested, as well as lawyers volunteering in local chapters.

“As an undocumented immigrant myself, I believe in Movimiento Cosecha’s mission,” Catalina Santiago, 22, told The Daily Beast. “As a DACA recipient I know I’m not deserving of protection from deportation, along with all the 11 million undocumented immigrants.”

Washington is not Santiago’s first NAA protest. She remembers cops coming to arrest people at the Boston protest, where she and thousands of others walked from the Holocaust Museum to Boston’s South Base detention center. But Santiago wasn’t worried. “It’s important not to allow the state to impose fear,” she said.

Michaela Caplan, a 23-year-old recent Dartmouth University graduate, who was arrested in New Jersey and helped coordinate the Boston action, went to the border over winter break. “I was surprised by how bad but also how normalized it was,” Caplan, who’s been arrested in protests twice before, told The Daily Beast. “I’m grateful for the sacrifice I and everyone else made by protesting and risking arrest, but we aren’t risking deportation.”