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(CNN) —  

The US government might send up to 20,000 undocumented immigrant children to housing on US military bases, two defense officials said.

The Department of Health and Human Services has assessed three bases in Texas and will visit a fourth in Arkansas, Pentagon spokesman Lt. Col. Jamie Davis said. The bases could be used as housing within a month if the pace of border crossings continues and no other solution is found, the defense officials said.

The Trump administration’s “zero tolerance” policy separated 2,300 children from their parents at the border in recent weeks. President Donald Trump signed an executive order on Wednesday, which he said was a way to end separations. But confusion remains, including about reuniting those already separated. US Customs and Border Protection said Friday it has united about 500 children with their parents who had been referred for prosecution over illegal entry.

The military would have no responsibility for any of the HHS-led activities, defense officials said. They likened it to being a landlord but not responsible for management of housing, security, food services or other activities.

Still, the possibility is drawing the Pentagon closer to a contentious issue, military officials told CNN.

“The optics are bad,” one said, adding that housing children at the bases could cause local civilian demonstrations.

Several officials emphasized that the possibility of housing undocumented immigrant children on military bases had existed during the Obama administration. But “we know the rhetoric is higher now,” one said.

HHS assessed Little Rock Air Force Base in Arkansas this week. The department also has completed site surveys at Dyess and Goodfellow Air Force bases in Texas, and Fort Bliss in Texas and New Mexico.

HHS will determine if the buildings or areas on bases meet basic housing standards and then would hire contractors to provide services.

The Pentagon would have to agree that it has the capacity and that military readiness and activities would not be interrupted, defense officials said.

CNN’s Nick Valencia contributed to this report.