Among those protesting at the Washington area airport were four congressman, who say Customs and Border Patrol officials denied information on whether detained travelers remained at the airport and if the lawmakers could meet with any of those detainees.
Reps. Gerry Connolly and Don Beyer of Virginia, and John Delaney and Jamie Raskin of Maryland, all Democrats, were struck with frustration upon finding they wouldn't have access to an official from the agency or be able to visit the detainment facilities at Dulles. Two of the congressmen currently sit on the Congressional Oversight Committee.
Connolly told reporters they'd intended to sit down with CBP officials to "get some answers to some questions" but were denied.
"Is that really an unreasonable request?" Connolly asked.
DHS Press Secretary Gillian Christensen told CNN on Sunday that no one from the initial group affected by the executive order is still being held.
Beyer called it a moment of "constitutional crisis," adding the CBP had a "responsibility to be responsive to Congress and obey those congressional orders."
Speaking to CNN, both Congressmen told stories of constituents from their districts affected by the new action.
Connolly said he intervened in a situation Saturday night where a 71-year-old man with a heart condition had been detained and denied access to a lawyer until very late in the evening.
Beyer had been in touch with a family of Sudanese visa holders that are currently stuck in Dubai.
"It's a mother, her son lives in my district and is a permanent resident," said Beyer. "He's in a coma in an ICU in a Washington, DC, hospital. She got a hardship visa to come visit him and she was turned away."
Calling for a commitment to follow an order issued by the Virginia Federal Court, Raskin insisted that "the people who are running the border have got to make sure that there are lawyers available to anybody who is being detained or questioned."
For anyone who is detained, there's legal counsel available to anyone with questions -- at least after getting past customs.
More than 100 lawyers were waiting in the international arrivals terminal Sunday, offering to provide free council to anyone who had a question about how President Trump's executive action could affect their friends and families.
The group of attorneys, who have set up a hotline for legal help and committed to return to the airport Monday, took part in the protest as well. They added their voices to hundreds of others, welcoming anyone coming through the international terminal, arriving from abroad.
Delaney characterized the President's actions as "evil," "un-American" and against the country's core values.
In similar language, Connolly condemned the executive action as "illegal," and called on the crowd to "insist that the CPB organization be accountable to the American people and follow the laws."
He later added that detaining people with green cards was "unheard of," and "not constitutionally permissible."
This story has been updated.