With federal facilities running out of room, the Trump Administration is assessing whether military bases in Texas and Arkansas can house immigrant children who are apprehended at the U.S.-Mexico border without an adult relative or separated from parents.

The ongoing assessments are due to increasing number of minors under 18 years-old who are being held by the U.S. Department of Health and Human Services. The agency, which is responsible for caring for the children until they can be given to an adult relative, stated it already holds more than 10,000 children in a network of 100 shelters in 14 states.

Army Lt. Col Jamie Davis, a Pentagon spokesman, said Wednesday that the agency has completed assessments at three Defense Department facilities in Texas “for potential use for the Unaccompanied Alien Children program,” adding that the agency will visit another “installation in Arkansas this week.” The facilities are Goodfellow Air Force Base, Dyess Air Force Base, Fort Bliss and Little Rock Air Force Base, according to U.S. officials.

Using military bases in this way is not new. In 2014, the Obama Administration placed around 7,700 migrant children on bases in Texas, California and Oklahoma. The temporary shelters were shuttered after four months.

Health and Human Services has said that “additional properties identified by federal agencies are being evaluated … as potential locations for temporary sheltering as a routine part of its management of” shelter capacity. The agency also said “additional temporary housing is only sought as a last resort when current locations are reaching capacity.”

Currently, migrant children are being held in facilities run by the Office of Refugee Resettlement within the Department of Health and Human Services. One facility, a converted Walmart in Texas, was recently opened to reporters, igniting a media firestorm.

Family separations began earlier this year after Attorney General Jeff Sessions announced a new “zero tolerance” policy of referring all border crossings for federal criminal prosecution, which leads to children being separated as their parents are sent to jail.

Housing the children at the bases means that the Defense Department will join the growing list of federal agencies with a stake in the Trump administration’s latest crisis, including Health and Human Services, Department of Homeland Security, and the Department of Justice.

However, it might be avoided if Congress passes a bill to address the nation’s immigration issues, which has garnered worldwide attention. House Speaker Paul Ryan said Wednesday he would hold a vote on the issue after a Tuesday night meeting with the President and colleagues. The outgoing Speaker outlined a proposal, which his team sketched out with the White House, that meets each of Trump’s demands for an immigration bill.

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Write to W.J. Hennigan at william.hennigan@time.com.