(CNN) Government shelters holding immigrant children are about 92% full, according to a Department of Health and Human Services official, a sign that the backlog of those in detention has not abated.

The number of migrant children in shelters fluctuates daily and thousands have been caught in a backlog that has some confined for many months.

As of Thursday, the number of unaccompanied children in 100 shelters across 17 states was about 14,700, agency spokeswoman Evelyn Stauffer told CNN.

That's an increase from the 14,000 children that CNN reported in facilities at the end of November and a step closer to the network being at capacity.

The updated numbers were first reported by NPR.

About 50% of the children came from Guatemala, 28% from Honduras and 12% from El Salvador, HHS said.

As detention times increase, with some staying up to a year, caretakers have seen children exhibit mental health and behavioral problems, a source inside a large detention service provider previously told CNN.

The source said that the unaccompanied children are considered higher risk. And while, in years past, child shelters used to be mission-driven (to serve children), now they are at full capacity and more policy driven.

According to Immigration attorneys and advocates, complicated government rules are to blame for the backup.

Detention time increasingly 'six to 10 months'

Last spring, the Trump administration implemented new information-sharing policies between HHS and Immigration and Customs Enforcement that included stricter vetting of adults who sponsor unaccompanied children. It also required the fingerprinting of everyone in the home and the sharing of that information with ICE.

While the administration said the measure was paramount to ensuring the safety and security of children, the move sent shock waves of fear through the undocumented community.

And those fears were realized when ICE announced the arrest of dozens of sponsors who had come forward to claim their children.

"We've arrested 41 individuals thus far," ICE senior official Matthew Albence testified before Congress in September.

"Unaccompanied alien children are particularly vulnerable to human trafficking, exploitation and abuse," HHS spokesperson Mark Weber said in a previous statement to CNN.

According to Weber, it takes an average of 59 days to place a child with a sponsor -- with several children staying in custody more than 100 days.

Immigration attorneys and advocates worry about the potential side effects of the extended detention times and argue that not only is the confinement excessive but is a violation of the children's rights.

"They can say it's just to vet; but it's to target parents and to put fear on immigrant families," said Sophia Gregg, an attorney for Legal Aid Justice Center, a nonprofit organization that provides advocacy and legal support to immigrant communities.

Gregg argues a more accurate depiction of current detention times is increasingly "six to 10 months."

The Legal Aid Justice Center filed a class-action lawsuit in July in US. District Court for the Eastern District of Virginia against the Trump administration on behalf of children who were in custody in Virginia for over five months while relatives tried to take them home.

HHS would not comment on specific cases, and instead has pointed at the broken immigration system.

The agency has pointed to three factors: a larger number of children referred to it by the Department of Homeland Security, the protracted reunification of children separated under the "zero tolerance" policy, and the Trump administration's policy that resulted in a time-consuming -- but necessary -- step to ensure children are not handed over to criminals or human traffickers.