TORNILLO, Texas - Dozens of protesters sang Christmas carols for migrant teens held in tent facilities Sunday, even as the first signs emerged that the shelter is gradually shutting down.

At least one bus packed with detained teens left Tornillo on Sunday morning, according to one of the protesters who's been watching the site for the past two months.

Rep. Beto O'Rourke, D-El Paso, made an unannounced visit and joined protesters who traveled as far away from New York, Ohio, Colorado, California, New Mexico and throughout Texas, including a group of more than a dozen from Dallas, many of whom traveled separately.

O'Rourke said he spoke Sunday to the top private contractor at Tornillo who said that as of last Tuesday "they have no longer been accepting children." He also told O'Rourke that the facility has at least 300 children ready to leave and their "only limitation right now is finding flights during the Christmas holidays."

The private contractor asked O'Rourke to share the news with the public in case passengers wish to voluntarily give up seats, said O'Rourke. BCFS, the private contractor, couldn't immediately be reached comment.

"If he's able to remain strong and not accept any more children," O'Rourke said, "by mid-January, Tornillo will shut down."

The crowd erupted in applause with the news, though O'Rourke and others called on protesters to remain vigilant and hold the Trump administration and BCFS, the private contractor, accountable.

1 / 3Joshua Rubin of Brooklyn, N.Y., holds up signs to passing vehicles going over the border or to the Health and Human Services encampment or tent city adjacent to the Tornillo Port of Entry on Thursday, November 8, 2018. He has been keeping a vigil outside the main border gate for the past couple of months and is planning to stay until it's closed or through the new year. The Witness Tornillo in the window is his Facebook group. The fenced compound is housing more children and has expanded since opening in June. (Tom Fox / Staff Photographer) 2 / 3Cheryl Pollman and the Rabbi Kim Herzog-Cohen, right, traveled from Dallas to Tornillo and held signs on December 23 to protest detention of the youths at the tent city.(Alfredo Corchado / The Dallas Morning News) 3 / 3April Dawkins, 42, and her father Spencer Dawkins, 64, drove 10 hours from Dallas to sing Christmas carols and protest the detention of youths at the tent city in Tornillo on Dec. 23, 2018.(Alfredo Corchado / Staff Photo)

BCFS has at least twice said it would not continue to operate the tent city once its contract expires, only to renew again. The latest renewable contract expires at year's end.

Taxpayers have spent more than $140 million since the "temporary" facility went up in early June, just before Father's Day.

"I'll believe it when I see it," said Diana Martinez, a humanities and history instructor at the University of Texas at El Paso and El Paso Community College.

A statement issued Monday by the U.S. Department of Health and Human Services said ""We are working towards the release of UAC to suitable sponsors as soon as possible in accordance with ORR's safety and child welfare guidelines. Our focus is always on the safety and best interest of each child. These are vulnerable children in difficult circumstances, and HHS treats its responsibility for each child with the utmost care."

The DHS statement also said most unaccompanied minors at Tornillo and "are about to be released to a suitable sponsor."

As of last week, about 2,800 children were detained at Tornillo, about an hour drive southeast of El Paso. Most have sponsors, usually family members, who have stepped forward to host them in the U.S.

The Trump administration had created a months-long administrative backlog by requiring every adult in a sponsor's household to undergo an FBI fingerprint background check before the children, ages 13 to 17, can be transferred to their care while awaiting the outcome of their asylum cases in immigration court. Most are males.

Last week, following public pressure and a widely publicized visit to the tent city by a congressional delegation headed by O'Rourke, the Trump administration reversed course on the fingerprinting policy, thus easing screening of potential sponsors.

The Department of Health and Human Services said it may be able to send thousands of migrant youths to relatives or other temporary guardians by Christmas.

Beto O'Rourke thanks protesters for bearing witness in Tornillo and pressuring the Trump administration to change its immigration policy, in Tornillo, Texas, outside the child detention 'tent city' on Dec. 23, 2018. (Alfredo Corchado / Staff Photo)

Joshua Rubin, a software engineer-turned protester who left Brooklyn two months ago in his RV camper and parked it outside Tornillo, witnesses the daily comings and goings at the facility. He got tired of being outraged of watching children separated from their parents due to Trump's immigration policies. He said goodbye to his wife and adult son and left for the border.

Because information on conditions at the camp is hard to obtain, Rubin said, he created a Facebook page, Witness: Tornillo.

And he diligently counts buses that go in and out, as well as vans. His goal is to hold President Donald Trump accountable for "his inhumane policies."

On Sunday, he saw the bus packed with teens inside leave the camp. He said he doesn't know where they were going, "but there were a lot of kids inside." On Monday, he posted that another bus packed with kids left the facilities.

Lately, he said, there seems to be movement. "Activity has picked up," he said, and repeated a vow to not leave the area until "we have justice and these kids are reunited with their families, and this place is shut down."

O'Rourke thanked Rubin and others who since June have turned Tornillo into a place of resistance to Trump's hard-line immigration policies. They include Spencer Dawkins, 64, who drove 10 hours with his daughter, April, 42, from Dallas.

"My inspiration isn't to spread compassion," he said. "This is about finding justice."

April added: "When you know things are wrong, you do what you can to stop it. That's why we're here."

Ana Fores, also from Dallas, came with her husband, Andres Pacheco, and her dog, Beckett, an Irish wolfhound. A refugee from Cuba, Fores said, "Back then, we were welcomed. People today are not very welcoming anymore. I'm here as a reminder of what our values are."

Cheryl Pollman and the Rabbi Kim Herzog-Cohen (right) also traveled from Dallas and held signs with a passage to serve as a message to Americans and Central American youth detained in Tornillo, Texas, outside the child detention 'tent city' on Dec. 23, 2018. (Alfredo Corchado / The Dallas Morning News)

Cheryl Pollman, 64, helped organized faith groups, including members of the Temple Emanu-El congregation in Dallas, travel to Tornillo. She plans to volunteer at Annunciation House this week to help feed migrants. Pollman said she's inspired by her own ancestors, including her grandparents, who fled from Poland and Russia following World War II to seek refuge and opportunity.

"My grandparents came when there was no structures at international ports of entry," said Pollman, adding that she's opposed to the building of walls to replace existing fencing along the border. "This is nothing more than stoking fear against those of color. It's a way to have someone to blame."

Rabbi Kim Herzog-Cohen said, "People are never without their walls, whether emotional, spiritual, mental, or psychological. We all have a moral obligation to follow our curiosity to come see what's happening on the ground."

Herzog-Cohen and Pollman carried signs in Spanish and English with a universal message that read, "The Exodus. We're all strangers in Egypt and we treat the sojourners justly and fairly." Said Herzog-Cohen: "In every generation there is a mandate within our faith, that we were all strangers and to some extent we still are."

Caroling on Sunday was just one in a list of activities known as 'Christmas in Tornillo,' said Martinez, adding, "Our goal is to shine a spotlight on what this administration is doing, especially the Department of Homeland Security."

Correction at 1:30 p.m. on Dec. 24, 2018: An earlier version of this story incorrectly stated that unaccompanied immigrant minors are subject to the Flores settlement. That court agreement limits the time children in the company of their immigrant parents may be held in federal custody to 20 days and does not apply to unaccompanied minors.