A vehicle drives into the Otay Mesa detention center in San Diego. (Elliot Spagat/AP)

A Congolese mother detained by immigration officials thousands of miles apart from her 7-year-old daughter was released Tuesday, according to the American Civil Liberties Union.

The woman, an asylum seeker who fled violence in Congo, has spent the past four months in a detention center near San Diego while her daughter has remained alone in a facility in Chicago. Last week, the ACLU filed a lawsuit on behalf of the mother and daughter, saying there was never any legitimate reason to separate them. The lawsuit accused the Trump administration of violating the pair’s constitutional rights and demanded that they be reunited immediately.

On Tuesday, immigration officials appeared to bend halfway in favor of the family’s lawyers, abruptly releasing the mother from custody at the Otay Mesa Detention Center in San Diego. The girl, however, remains in the custody of the Office of Refugee Resettlement in Chicago, and the pair are still awaiting reunification, the ACLU said. It is unclear when the mother and daughter might be reunited.

“We are thrilled that the mother has been released and look forward to the government immediately reuniting her with her daughter,” Lee Gelernt, deputy director of the ACLU’s Immigrants’ Rights Project, said in a statement. “But there remain many other families who have been separated, and we will continue to attack this horrific family separation practice.”

The woman’s release came under orders “from up top” in the U.S. Department of Homeland Security, Gelernt told the Associated Press. A spokesman from U.S. Immigration and Customs Enforcement didn’t immediately respond to a request for comment Tuesday night.

“This case hit a nerve for a lot of people because it’s so unconscionable what this government has done … to separate a mother from her daughter for no reason at all,” Judy Rabinovitz, deputy director of the ACLU Immigrants’ Rights Project, told The Washington Post in an interview Wednesday morning. “Obviously DHS was feeling some pressure.”

Last week’s lawsuit drew national headlines and intense scrutiny from immigration advocates. The case underscored Trump’s crackdown on immigration and marked a shift from previous administrations, which detained families but did not forcibly separate parents from their young children, the ACLU said in its lawsuit.

The Obama administration implemented a policy of holding women and children together at family detention centers for no more than 21 days before releasing them. But the Trump administration has floated a proposal to begin separating asylum-seeking parents from their children, officials told The Washington Post in December.

Officials have not yet formally announced a policy of separating women and children, but Rabinovitz said, “We know that they’re in fact doing it, and that they need to stop.”

“We hope that this sends a strong message to the Trump administration,” Rabinovitz said.

In a statement tweeted Sunday, DHS spokesman Tyler Q. Houlton said immigration officials retain the authority to separate women and children in certain circumstances, “particularly to protect a child from potential smuggling and trafficking activities.”

If authorities are unable to confirm a parent-child relationship, they may be obligated to place the child in the custody of the U.S. Department of Health and Human Services, according to the DHS statement.

“If we were to fail in this regard we could be responsible for allowing a child to be released to a trafficker, which is clearly unacceptable,” the DHS statement read. “We ask that members of the public and media view advocacy group claims that we are separating women and children for reasons other than to protect the child with the level of skepticism they deserve.”

The mother and daughter, identified only as Ms. L. and S.S., respectively, escaped from Congo fearing “near certain death,” according to the ACLU lawsuit. The family is Catholic and sought refuge in a Catholic church before fleeing their country.

On Nov. 1, they arrived at a U.S. port of entry near San Diego and told border guards they sought asylum. Their native language is Lingala, a language spoken throughout Congo and other parts of central Africa. They managed to communicate with immigration officials using the minimal Spanish they knew.

In an initial screening, an asylum officer determined the mother had a “significant possibility of ultimately receiving asylum,” according to the lawsuit. This made her eligible for release on parole while her asylum case proceeded, her lawyers argued. But the San Diego ICE field office has a policy of refusing to grant parole to detained asylum seekers, the lawsuit stated.

During their first four days in the country, the mother and daughter were detained together in “some sort of motel,” according to the lawsuit. But they were then separated halfway across the country. The mother has not been accused of any abuse or neglect,  the lawsuit said.

When officers separated them, the woman “could hear her daughter in the next room frantically screaming that she wanted to remain with her mother,” according to the lawsuit. “No one explained to Ms. L. why they were taking her daughter away from her or where her daughter was going or even when she would next see her daughter.”

The pair have only occasionally spoken by phone in the months since. During these calls, the young girl “cries and is fearful of what will happen to her and her mother,” the lawsuit states. Her mother is “distraught and depressed. … She is not eating, has lost weight, and is not sleeping due to worry and nightmares.”

The Congolese woman’s lawyer was surprised by her release. Her immigration attorney received a call Tuesday saying the mother would be let out in two hours, even though the lawyer was far from the San Diego facility at the moment, Gelernt, of the ACLU, told the Chicago Tribune. The attorney was told the mother was a “mandatory release regardless of whether she has anywhere to go.”

The woman’s lawyer managed to reach the mother and planned to arrange a hotel for her, Gelernt told the Tribune.

“I think they won’t reunite her with her daughter until she has a stable place,” Gelernt told the Tribune. The ACLU plans to immediately find her a more permanent place to live, he said.

Rabinovitz criticized the abrupt way in which officials released the mother, “without any kind of advance planning for where she was supposed to go.”

“For people who don’t have those kind of resources,” she said, “I don’t know what would have happened.”

More from Morning Mix:

Cecil the lion ‘suffered incredible cruelty for at least 10 hours,’ new book says

Hate your selfie? There may be a good reason, says new study.

Gary Oldman’s son blasts ‘clickbait’ media for resurfacing 17-year-old assault allegation against the actor