Updated at 8:55 a.m.

DULLES, Va.—An enormous cheer erupted from the circle of lawyers when one of them read out the news from his Twitter feed: The American Civil Liberties Union had been granted a stay by a federal judge in New York that would temporarily halt parts of President Donald Trump’s executive order limiting immigration from seven Muslim-majority countries. He scrolled a bit more. “And it’s national!” More cheers.

It’s the announcement the attorneys had been waiting for since they began arriving at the international terminal of Dulles International Airport three, four, even five hours before. They’d been milling about at the end of a long human tunnel formed by hundreds of protesters, flashing signs that read “Free legal help!”

The demonstrators chanted welcoming slogans, denouncing the executive order that Trump signed Friday. The order was so broad that even people from those countries who held student visas, work visas, and green cards—or who held another non-U.S. passport—were held up at the border. Some were let through; others were held for hours. The gathering at the Washington, D.C.-area airport mirrored others around the country.

Passengers who made it through customs and immigration at Dulles were greeted with shouts and whoops as they emerged into the hall. Some looked bewildered, others smiled, and a few jumped and danced and reveled in the attention. A Moroccan family that emerged through the crowd was beaming. “It’s the first time I’ve seen anything like this,” said one family member, who had never visited the U.S. before.

The attorneys were there in force, for hours far outnumbering the people they were trying to help. Many had name tags that identified them as lawyers, and even on a Saturday evening, they were dressed in suit jackets and button downs. Some saw a call for attorneys on social media; others were on a listserv that blasted out details. Still others filled out a Google Doc with their information and were routed to the airport nearest them.

The army of attorneys had been marshaled by the International Refugee Assistance Project, but the lawyers I met all came from different organizations. Some had private immigration practices, others didn’t practice immigration law at all. Some just turned up on their own, without knowing something was being organized, and they joined the throng.

When news that a judge in New York had granted a stay came in, just before 9 p.m., the lawyers were jazzed—but they still knew little. “They need to let us back there now!” one said. A colleague wanted to know when that would actually happen. “Soon. But soon is a relative term.”

“This response is really just sort of organic,” said Judah Ariel, who was serving as the point of contact for arriving lawyers. “We’ve been having to coordinate it ourselves. There’s a ton of uncertainty, so a lot of what we’ve been doing today is to try and figure out what’s going on.”

Nobody knew just how many people were being held on the other side of the wall. Some lawyers guessed that there were between 50 and 60 people being detained—but that was before another flight came in from Istanbul. Since then, it appears that several Iranian green-card holders were released.

It appeared that most of those in detention were people with green cards or visas. That could be because refugees usually arrive on weekdays, an employee at a refugee-rights organization said. It could also be that refugees weren't even allowed on U.S.-bound planes, said a lawyer.

Without access to the detainees, the lawyers couldn’t do much. They were trying to get in touch with people being held through family members who were allowed through. “We want to make sure that they don’t sign anything,” said Mirriam Seddiq, an immigration attorney based in Maryland. “And if they try to put you on a plane to go back, sit your ass on the floor.”

Many of the people who showed up in the arrivals hall Saturday night—attorneys or demonstrators—were particularly shocked that green-card and visa holders were being detained. “They live here,” said Ariel. “Permanently. I just can’t imagine being on  a business trip or visiting a family member and, all of a sudden, finding out that, oh, by the way, you’re not allowed back home.”

A young couple stood near the swarm of lawyers, but turned to cheer the passengers making their way through the tunnel of demonstrators. I asked them why they’d come. “As Iranian immigrant refugees, it’s our duty to come,” said Asad Saghafi, whose hair was pulled back into a short bun. He’d come along with his fiancée, Javaneh Pourkarim, who offered her services as a lawyer to the coordinators. After someone took down her information, the two gravitated back toward the protesters.

“We were raised here, we grew up here, but we don’t feel like we belong here right now,” said Saghafi. He arrived in the U.S. in the late ’80s, during the Iran–Iraq War. Pourkarim came just over a decade later. Both are naturalized U.S. citizens now. “For me, it’s the first time in 17 years that I don’t feel welcome here. That I don’t feel secure,” said Pourkarim.

“Well, except for in this moment, with all of these non-Iranians and non-Muslims coming together,” Saghafi said. “That’s really nice.”

By midnight, lawyers still hadn’t been let in to see detainees—despite the fact that a federal judge in the Eastern District of Virginia signed a restraining order requiring Customs and Border Protection to allow the attorneys in. Siddiqi said she was told that the officers were still waiting on instructions from lawyers at the Department of Homeland Security. Just before midnight, Cory Booker, a Democratic senator from New Jersey, arrived at Dulles Airport to try to get access for the lawyers.

Attorneys began reassembling at Dulles Sunday morning, but were still being denied access to detainees. At least one Syrian national appeared to still be held by CBP officers, but others may have been transferred elsewhere overnight.

A DHS official told NBC News that 109 travelers from the seven Muslim-majority countries were denied entry to the U.S., and that 173 were prevented from boarding U.S.-bound flights. The official said that a total of 375 travelers were affected on Saturday.

But even as they fought to be let in on Saturday night, the lawyers were heartened by the support in the arrival hall. “If people have lost faith in America after last night, come here. You’ll get it right back,” said Seddiq. “If you feel hopeless, just come here. You won’t feel hopeless anymore.”