WASHINGTON: The US military opened an army base in Texas for migrant children Tuesday as the number of unaccompanied children and families crossing the border from Mexico mounted.

The Department of Health and Human Services, which is charged with resettling thousands of migrant children who crossed the border without their parents, said it moved 500 into facilities at Fort Bliss, a base located just three miles (five kilometers) from the US-Mexico border in El Paso.

Eventually HHS hopes to provide shelter at Fort Bliss to up to 5,000 male migrants as its number of beds are increased.

"The children will be welcomed by staff, receive a brief medical check, provided needed clothing, toiletries, food and snacks, as well as a safe place to rest," said the HHS Administration for Children and Families, which helps manage the resettlement program.

According to government statistics, on Monday HHS had 12,035 migrant children in its care, while the US Customs and Border Protection, the agency which first processes migrants, was holding another 4,068.

The administration of President Joe Biden has committed to allowing children under 17 who cross the border without parents or family to remain in the United States, a decision that critics say is encouraging more to make the risky journey north.

The numbers continued to mount, with a recent average of nearly 500 unaccompanied children crossing the border into CBP hands each day.

Meanwhile HHS has only been able to place 200 to 300 every day with relatives inside the United States.

Added to that are hundreds of migrants, predominantly from Central American countries, crossing the border in family units. Most are pushed back across the border but in some areas Mexico is refusing to take them.

The children have overwhelmed CBP and HHS facilities, bringing criticism of Biden for overcrowding and forcing a rapid search for new capacity to hold them, as in Fort Bliss.

On Tuesday immigration officials opened up some of its facilities in Donna, Texas to reporters for the first time, in an effort to show the migrant children are being treated humanely.