The aggressive plan comes at the same time that child shelters are filling up with more children who have been separated from their parents. The number of migrant children held in U.S. government custody without their parents has increased more than 20 percent as Attorney General Jeff Sessions and Homeland Security Secretary Kirstjen Nielsen rolled out the administration's new policy zero tolerance policy that separates children from their parents who now face prosecution.

The Office of Refugee Resettlement at HHS is responsible for the care of more than 11,200 migrant children being held without a parent or guardian and must routinely evaluate the needs and capacity of approximately 100 shelters , which are now 95 percent full.

Because of the large fluctuations in referrals of unaccompanied minors, the administration said its appropriate to have a mix of “standard” beds that are available year-round, and “temporary” beds that can be made available to address any increases in migration flows. HHS can place unaccompanied children in an appropriate setting while a sponsor is identified who can care for the child while their immigration case proceeds. It helps protect the border but also prevents vulnerable kids to fall into the hands of traffickers, officials said.

“The lack of parental protection, and the hazardous journey they take, make unaccompanied alien children vulnerable to human trafficking, exploitation and abuse,” the HHS official said.

Trump has blamed Congress for allowing the loopholes that require federal authorities to release illegal immigrants to await hearings for which many don’t show up.

Deputy Attorney General Rod Rosenstein at a roundtable last month with Trump charged that those loopholes also prevent the administration from quickly deporting unaccompanied children.

“It can take months and sometimes years to adjudicate those claims once they get into the federal immigration court system, and they often fail to appear for immigration proceedings,” Rosenstein said. “In fact, approximately 6,000 unaccompanied children each year fail to appear when they've been summoned. They're released and they don't show up again.”

Tens of thousands of unaccompanied children and families have been apprehended since 2014, when a surge of Salvadoran, Honduran and Guatemalan mothers and children raced into the Rio Grande Valley in Texas, fleeing violence and poverty.

The unaccompanied children are generally turned over to family or held in an HHS shelter, like a detention center or tent city. Now those who arrive with their parents are being separated from them and also sent to HHS shelters or sponsor families.

Leon Fresco, a deputy assistant attorney general under President Barack Obama, who defended that administration's use of family detention, said the Trump administration is also likely going to need to return to Congress soon for more money if it wants to keep up this aggressive detention approach. He said it's much more expensive to separate the parent and children and hold them in two different facilities than keeping them together using a monitoring system.

“The point is separating families is not only controversial, it’s also inordinately more expensive,” Fresco said.

Advocates accused the Trump administration of using the children as pawns to score political points.

“Detaining children for immigration purposes is never in their best interest and the prospect of detaining kids in tent cities is horrifying,” said Clara Long, U.S. researcher at Human Rights Watch. “US authorities should focus on keeping families together, ensuring due process in asylum adjudications and protecting the rights of children."