A child from El Salvador clings to his mother after she surrendered to U.S. Border Patrol agents near Rio Grande City, Tex., in December. (John Moore/Getty Images)

With the number of migrant children in government custody rising fast, the Trump administration said Thursday that it will open an additional temporary shelter in the desert outside El Paso. 

The shelter site, at the Tornillo-Marcelino Serna port of entry, is about 20 miles east of El Paso along the Mexico border. It was last used in 2016 to house migrant children and families in large, dormitory-style canvas tents.

Children will begin arriving in the next few days, according to the Department of Health and Human Services, which is responsible for their care. The site will have 360 beds, according to HHS officials, with the potential to add more. The Tornillo site will be the only location, to date, where HHS plans to put children in tents, or what the agency calls “semi-permanent structures.”

HHS said Thursday that it had 11,432 migrant children in its custody, up from 9,000 at the beginning of May. The numbers include minors who arrived at the border without a relative as well as children separated from their parents as part of the administration’s “zero tolerance” push to file criminal charges against anyone who enters the United States illegally.

The Tornillo site belongs to the Department of Homeland Security. It will have recreation areas and educational programming, and its tents are air-conditioned, according to HHS spokesman Kenneth Wolfe.

“HHS is legally required to provide care and shelter for all unaccompanied alien children referred by DHS, and works in close coordination with DHS on the security and safety of the children and community,” Wolfe said in a statement. 

The shelter would not interfere with operations at the border crossing, Wolfe added. “This effort has no impact on the ability of DHS to conduct its primary missions,” he said.

Texas state Rep. Mary González (D) whose district includes the Tornillo area, said in a statement Thursday that the port of entry is unable to care for hundreds of children. “This is not a place that was built to house children, nor is it a location that has adequate numbers of counselors or therapists to assist these children,” she said.

On average, migrant children spend more than 50 days in HHS care while the agency identifies and screens potential sponsors — usually a relative living in the United States — who can assume custody.

The vast majority are held in a network of about 100 shelters around the country, including one at a repurposed Walmart with nearly 1,500 boys in Brownsville, Tex., visited by The Washington Post and other news outlets this week.

Homeland Security opened the Tornillo-Guadalupe Temporary Holding Center in 2016 to house families and unaccompanied minors, but the facility shut down after a few months. With a sharp increase this spring in the number of children taken into government custody, HHS officials said they have been scouting locations where they could install thousands of additional beds. 

Rep. Will Hurd (R-Tex.), whose district includes the Tornillo area, sponsored legislation in 2016 to name the port of entry there for Marcelino Serna, the most-decorated Texas soldier in World War I. Serna joined the Army in 1917 to avoid deportation to his native Mexico.

Robert Moore in El Paso contributed to this report.