Immigration activists in Philadelphia say a warning issued to a Berks County holding center for refugee children and their families has them optimistic, but it doesn’t go far enough. 

The Berks County Residential Center is one of the few in the nation that detains immigrant families, and the only one in the country that accepts families headed by men.

The facility, which holds families seeking asylum or who are being detained for immigration violations, has seen massive backlogs since waves of immigrant children from Central America began crossing the border in Mexico last year. 

Advocates say that the facility keeps children in prison, though they have not been accused of any crime. 

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They have fought to close the facility, saying no provision of Pennsylvania law allows for detention centers that mix adults and children.

In a letter to the facility sent Thursday, DHS Secretary Ted Dallas wrote that Pennsylvania regulators said that the “current use of the Berks County Residential Center is inconsistent with its license as a child residential facility.”

Federal immigration authority have struggled to manage the waves of immigrants who arrived in the U.S. last year, often fleeing gang violence and crushing poverty. 

Officials in Berks County have asked the state for permission to expand the center’s maximum capacity from 96 to 192 beds. 

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In his letter to the center, Dallas warned the state won’t act on its request to expand unless the county commits to ceasing its current use “as a secure facility for refugee children.” The department could revoke the center’s license in February if changes aren’t made.

Erika Almiron, executive director of Vamos Juntos, said Friday that immigrant groups want the U.S. to stop the deportation of families. 

“We have not won yet, not until every family is out of that detention center,” Almiron said.