Barack Obama has increased contingency funding for the unaccompanied minors crossing the U.S.-Mexico border illegally in the past two months, but his administration admitted that there is still shortage of finances to house the children.

In a letter issued to Connecticut Rep. Rosa DeLauro, Sylvia Burwell, the secretary of the Department of Health and Human Services, or HHS, said that despite the rise of contingency funding requested by the president, the agency experiences financial deficiency that could result to a border crisis, similar to "the situation we faced in (2014) when children were left at the border for unacceptable periods of time," the Guardian reported.

"While it is impossible to know if these trends will continue for the duration of the fiscal year, we are very concerned about having adequate resources to meet the needs of the unaccompanied children that are being referred for HHS services," the secretary wrote in the letter obtained by Politico.

Agency spokesman Mark Weber said that Burwell is speaking with Congress members to ensure that they are prepared, and that the letter doesn't demand funds beyond Obama's budget request, the Guardian added.

In October and November, the U.S. Border Patrol recorded a total of 10,588 unaccompanied children crossing the U.S.-Mexico border, an uptick from the 5,129 who arrived during the same two months last year, the Guardian wrote. The increase has already pushed the agency to open two shelters in Texas and in California.

Obama's administration is looking to avoid replicating the crisis in the summer of 2014, when tens of thousands of children and families surged over the southwest border. Border Patrol holding areas "became overcrowded, with children sleeping on concrete floors covered by aluminum foil-like blankets," the news outlet noted. There were also an outpouring of children arriving unaccompanied, which the U.S. government and the White House labeled as "a humanitarian crisis."

The law dictates that unaccompanied child migrants from countries that don't border the U.S. must be handed over to the HHS within 72 hours of being detained, the Guardian reported. The government is responsible for their welfare until they are united with a relative or sponsor in the U.S., which allows immigration courts to rule on their cases.

Burwell said that immigrants -- who commonly hail from El Salvador, Guatemala, and Honduras -- leave their home countries due to several reasons, such as "economic instability, drought, and violence in Central America," Politico listed.

Mexico has taken action on migrants within its borders and returned plenty of them to their home countries, the Guardian wrote. However, experts said that smugglers have devised new ways around checkpoints and have established new bribery networks to get migrants across the border.