The Obama administration has lost track of scores of immigrant children who have been caught crossing into the United States illegally, according to a new government oversight report that found children are sometimes being placed into homes with other illegal immigrants and non-citizens.

Following a massive uptick in the number of immigrant children crossing into the United States, the Government Accountability Office discovered that children are being handed off to individuals who have not gone through vigorous background checks and may have criminal histories.

Regulations do not require that individuals taking custody of these kids "be a citizen or lawful permanent resident of the United States," according to the report, which has sparked investigations on Capitol Hill into the Obama administration’s handling of these immigrant children.

Federal officials followed up with just 2.2 percent of the children who were released into sponsors’ homes after their apprehension on the border in 2014, according to the study, which disclosed that a total of 53,518 immigrant children were released from federal custody during that time.

Oversight officials found that the Office of Refugee Resettlement has failed to properly track children once they are released and is not keeping complete case files, a situation that is endangering these children and leaving them vulnerable to abuse and trafficking, immigration experts say.

The agency also has failed to monitor the groups it contracts with to ensure that they are providing proper care to these children.

The report was released the day before a Senate Judiciary Committee hearing that will address "the unaccompanied children crisis."

Around 125,000 unaccompanied minors from Central American countries have been apprehended at the U.S.-Mexico border since 2011. Most came from El Salvador, Guatemala, and Honduras. Officials expect the number to rise in 2016.

"These children were released in every state except one," according to the report. "The largest number of children were placed in Texas, New York, California, Florida, and the Washington, D.C., area, respectively, with Harris County, Texas receiving 4,028 children in fiscal year 2014, more children than any other single county."

In order to more quickly move these children out of federal shelters, the Refugee Resettlement Office relaxed the level of background checks and verification methods that are employed to ensure children are being released into a safe household.

This includes simplifying "documentation requirements for sponsors by eliminating notarization requirements and allowing photocopies (rather than original copies) of supporting documentation, such as birth certificates," the report found. The agency "also removed the fingerprinting component of background checks for parents and legal guardians."

The federal government handed off most of these responsibilities to independent contractors, which were found to be operating with little oversight. Officials could not determine whether the contractors provided the services they claimed.

Documents were "often missing" from the 27 random case files that oversight officials selected for review.

"None of the 27 case files we reviewed contained all of the required documents to verify the services provided," the report found, "Specifically, 14 case files were missing the Know Your Rights legal presentation acknowledgement form, 10 were missing a record of group counseling sessions, and 5 were missing clinical progress notes. In addition, we identified several cases in which forms that were present in the files were not signed or dated."

"Project officers found that facility staff had failed to medicate children properly, including, in one instance, accidental overdoses of medicine," the oversight officials found during inspections of these facilities.

Once released from federally operated shelters, children were transferred into the custody of sponsors, which can be family members, relatives, or unrelated individuals.

The refugee agency often failed to follow up with these families once releasing the children.

"A relatively small percentage of unaccompanied children received post-release services, and [the Office of Refugee Resettlement’s] responsibility for the other children typically ended once it transferred custody of the children to their sponsors."

Immigration experts described this policy as dangerous, particularly when it comes to vulnerable minorities who may have already experienced trauma.

"These findings confirm that the administration’s response to this influx of people has been nothing short of a disaster, and this is just one more manifestation of it," said Jessica Vaughan, director of policy studies for the Center for Immigration Studies.

The administration is "putting kids at risk of harm and abuse," Vaughan said, explaining that in some cases the administration is "actually turning trafficked kids over to their exploiters."

"In their zeal to pretend that this whole phenomena was something harmless, they neglected their responsibility to make sure they were not making matters worse," she said. "They’ve completely failed in that responsibility."

In some instances, local officials in communities where children had been resettled were unaware that the federal government had done this.

"In two of the counties in which we conducted phone interviews, representatives from mayors’ offices told us that they were unaware that unaccompanied children were living in their city or had limited knowledge about the issue," according to the report.

A large portion of these immigrant children has applied for asylum status in the United States.