PHILADELPHIA — Lawyers for asylum-seeking families being held at a detention center in Pennsylvania are petitioning to intervene in a case that will determine whether the facility can keep its license, arguing the state should move faster to shut it down.

The Berks County Residential Center, north of Philadelphia, is one of three family detention centers in the United States that hold children and parents who have entered the country illegally. The low-security facility is run by the county through a contract with U.S. Immigration and Customs Enforcement.

The center's population has fluctuated as some detainees have been freed and others have been deported. Advocates estimate it still holds around 30 families, including children as young as 1.

Aldea — the People's Justice Center, a nonprofit group representing the detainees, filed a petition this week to intervene on behalf of current and former residents as an administrative law judge considers whether the center qualifies for a license.

In 2016, the state Department of Human Services decided against renewing Berks' child residential license, on the grounds that adults could not also live in such a facility. But a judge last year ruled the decision was arbitrary and the result of political pressure, and he ordered the license restored. He said the state had always understood that adults lived with children at the center, first licensed in 2001.

The state is disputing the decision was arbitrary and is asking the judge to reconsider his ruling.

Aldea also is seeking the right to present evidence in the case in support of a swift closure. They argue that because the state oversees the facility, it cannot effectively litigate on behalf of the residents over the license.

"This is just an issue of looking out for the people who are detained there, making sure that their needs and their interests are represented," Aldea member Carol Anne Donohoe said.

Democratic Gov. Tom Wolf, who took office in 2015, has urged that the families be moved to community settings.

Immigration and Customs officials said in a statement that the agency "takes very seriously the health, safety and welfare of those in our care," and it pointed to last year's decision that the license revocation was unwarranted.

The Department of Human Services has investigated every allegation made against the center and "to date has not found cause that would warrant emergency closure," agency spokesman Colin Day said.

"The facility continues to operate while pending appeal, as is its right to due process," Day said.

Aldea's advocates presented 360 pages of evidence in support of their claims. They argue it's unlawful for minors to be held with adults at a child residential facility, and they allege instances of medical neglect.

The petitioners maintain that DHS could shut down the center during the appeals process.

"They have the power to terminate the license and not consent to the ongoing use of the facility while the appeal is pending," said Elizabeth Simpson, senior staff attorney at the National Immigration Project of the National Lawyers Guild and co-counsel on the petition.

"Berks is really running a prison for children," she said. "I think that it violates human rights."