The Trump administration wants to bring more unaccompanied minors to Northern Virginia and other parts of the country to relieve overcrowded detention centers at a southern border that officials say has reached “a breaking point.”

In a formal solicitation posted last week, the General Services Administration says it needs to lease long-term space in Northern Virginia, enough to house about 440 children who have arrived in the United States illegally without a parent or guardian. That would increase the number of children being held in federally funded shelters in Virginia fourfold.

The Department of Health and Human Services, which oversees the care of unaccompanied minors through its Office of Refugee Resettlement, is also looking for vacant space to lease in Los Angeles and central Florida, officials said, though they wouldn’t provide details on those locations.

The administration’s search for extra shelter space underscores the intense backlash in recent months over the squalid conditions in crowded federal shelters at the border, where visitors have described seeing unbathed children wearing clothes caked with snot and tears, toddlers without diapers and teenage mothers in clothes stained with breast milk.

Last month, a report from the Department of Homeland Security’s Office of Inspector General found “serious” overcrowding at U.S. Border Patrol detention centers in the Rio Grande Valley of Texas, where the number of unaccompanied minors apprehended — most of them arriving from Central America — jumped 62 percent in 12 months to nearly 24,000 in May.

“The current migration flow and the resulting humanitarian crisis are rapidly overwhelming the ability of the Federal Government to respond,” a Homeland Security official said in a memo responding to the report.

The Office of Refugee Resettlement is charged with finding ­longer-term shelter for unaccompanied minors and, where possible, reuniting them with relatives in the United States after conducting background checks.

The agency funds about 170 shelters in 23 states, with about 8,700 unaccompanied minors in those facilities.

In Virginia, about 130 unaccompanied minors are being housed in the commonwealth’s two largest federally funded shelters — Youth for Tomorrow in Prince William County and the Shenandoah Valley Juvenile Center in Staunton, immigrant advocates say.

The GSA solicitation says the administration is looking to lease close to 110,000 square feet for 15 years in an area that includes Arlington, Fairfax, Loudoun and Prince William counties, plus the smaller cities that surround those jurisdictions.

The lease is part of a plan by HHS to build permanent shelters in parts of the country where relatives of unaccompanied minors already live in hopes of eliminating the need to rely on temporary shelters when the flow of migrants at the border suddenly escalates, officials said.

Once completed, the “Virginia Residential Child Care Facility” would begin housing the children next spring, officials said.

The shelter would have a staff of 147 people and would be equipped with classrooms, sleeping areas and an extra two acres of outdoor space for recreation, the solicitation said. Bids for the lease are due Aug. 13.

The announcement caught local government officials and immigrant advocates by surprise.

Sharon Bulova (D-At Large), chairman of Fairfax County’s Board of Supervisors, said she was “puzzled,” given Northern Virginia’s expensive lease rates.

“This is one of the most expensive parts of the country, much less, in Northern Virginia, we are the most expensive part of the state,” Bulova said.

But, she said, “there are many nonprofits and charitable organizations in this area that would be glad to be supportive, I’m sure.”

Immigrant advocates said the idea of one large shelter for unaccompanied minors is worrisome.

“The notion that the same level of care could be provided at a 440-bed facility as at a 100-bed facility is a little hard to imagine,” said Simon Sandoval-Moshenberg, legal director of the Legal Aid Justice Center’s Immigrant Advocacy Program.

Sandoval-Moshenberg said the Trump administration should be working harder to reunite unaccompanied minors with relatives here.

“There are more cases that are taking forever, hundreds and hundreds of days,” he said. “We don’t believe that they would need facilities of that nature if they would more efficiently use the facilities they currently have by releasing more kids more quickly.”