A dozen travelers who’d been held at O’Hare International Airport were released late Saturday, ending a day in which 18 people were detained there due to an executive order signed by President Donald Trump.

All of those detained throughout the day had been released by 11 p.m., said Fiona McEntee, one of the lawyers with the American Immigration Lawyers Association who represented the travelers.

The chaotic day at the airport came a day after Trump signed the order barring refugees and green card holders from seven Muslim-majority nations from entering — or returning to — the country.

The chaos inside the international terminal during the day mushroomed into a massive protest outside of it Saturday evening. Thousands of protesters blocked car traffic into the terminal and forced authorities to shut down roads in and out of it, though the terminal itself remained open.

By midnight, after the detainees were released, the roads were reopened to traffic. Chicago Police said no one was arrested in the demonstration.

Similar protests ensued at airports across the country.

Dozens of attorneys crowded O’Hare’s international terminal for most of the afternoon Saturday, offering pro bono legal aid to anyone who said their family members were being held by authorities. U.S. Rep. Jan Schakowsky, D-Ill., said she’d been working Saturday to secure the release of those being detained.

By Saturday night, a federal judge issued an emergency order temporarily barring the U.S. from deporting people from nations subject to Trump’s travel ban, saying travelers who had been detained had a strong argument that their legal rights had been violated. It was unclear how quickly the order might affect people in detention or whether it would allow others to resume flying.

At O’Hare, McEntee was thrilled to see a day that began with so much uncertainty end on a happy note.

“I felt like we really saw democracy in action tonight with all the people that came out to show their support,” she said. “People bought us coffee and bought pizza. It was incredible.”

Just before 6 p.m. Saturday, the first person at O’Hare to tell attorneys his family was detained, Mohammad Amirisefat, was reunited with his sister, brother-in-law and their 6-month-old son, who were returning from visiting family in Iran.

After more than five hours of detention, Hessameddin Noorian and his wife Zahra Amirisefat, along with their baby son Ryan, passed through the gates of O’Hare’s international terminal.

Noorian said before being released he was interviewed for about a half hour.

“They asked us to sit there, no cell phone, no call, no nothing,” he said. “It was like 20 hours flight, and (we) were there for almost six hours, and I’m so tired.”

Noorian said he didn’t know Friday’s executive order applied to those like him who hold green cards.

“I thought as long as you have a green card, then you’re safe, you’re fine,” said Noorian, who along with his wife teaches at Oakton Community College.

Asked how it felt to be detained in a country where he lives, works and had a child, the Park Ridge resident said: “The only thing I could say is [it] seems something changed.”

Julia Schlozman, one of the attorneys who traveled to O’Hare at the request of the American Immigration Lawyers Association, helped resolve Noorian’s detention.

“I heard that there was a gentlemen being detained who had dual Iranian/British citizenship, and I had the idea, ‘Maybe the British government has something to say about the fact that a U.K. passport is not being recognized by U.S. immigration authorities,’” Schlozman said.

Schlozman called “an emergency line” in London to see if the British authorities could follow up, and they said they would. “I have no idea whether that had anything to do with any movement on the case, but I guess it was something,” she said.

Rep. Schakowsky said after making “non-stop” phone calls, she finally reached someone at the U.S. Department of Homeland Security, leading to Noorian’s release.

“It’s unbelievable,” she said.

Schakowsky said lawyers gathered at the airport asked her to help those who were being questioned at O’Hare, most of them Chicago-area residents. Their situations demonstrate Trump’s crackdown is affecting more than just refugees but also people who’ve been living in the U.S. legally.

Among the group detained at O’Hare on Saturday, Schakowsky said, were:

• An Oak Park man originally from Iran who has a U.S. green card. He is a dual citizen of the United Kingdom and Iran.

• A South Loop man from Iran with a green card.

• A woman from Ohio who has applied for a green card with her 2-year old daughter who is a U.S. citizen.

• A couple living in Crystal Lake who have Syrian passports.

• Three members of a North Side family from Pakistan who have F2 visas.

Others with green cards included an elderly woman from Iran, a man from Iraq and a man from Yemen who has lived in the U.S. for 18 years.

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Throughout the day, Democratic politicians decried Trump’s immigration crackdown.

“There are families stuck at ORD tonight — children who don’t know when, if ever, their parents will come HOME,” U.S. Sen. Dick Durbin, D-Ill., said in a tweet.

He also tweeted: “These executive orders are tearing families apart and playing right into our enemies’ hands. This isn’t who we are.”

U.S. Sen. Tammy Duckworth said “stopping legal permanent residents and babies simply because of where they’re from is not the American way, and it doesn’t make us safer. This Muslim ban must end.”

Congressman Mike Quigley said Trump’s executive order has “very real and dangerous consequences” and should be rescinded immediately.

“As a Member of the House Intelligence Committee, I am convinced that sweeping bans on whole categories of immigrants and refugees is deeply harmful to our national security interests, further complicating the fight against ISIS and other terrorist groups. Moreover, banning a group of people strictly on the grounds of their religion is unconstitutional and disrespects the legacy of our nation’s founders.”

Chicago Mayor Rahm Emanuel said Trump’s action tarnishes America’s image in the world.

“Those kids being stopped, whether they’re from Syria or another country, are part of a humanitarian crisis,” Emanuel said. “This undercuts who we are and what we stand for.”

Lawsuits also had begun being filed in federal court in Chicago on behalf of some of those being detained. It was unclear whether those actions would proceed now that the detainees had been freed.

Contributing: Associated Press, Jon Seidel