BROWNSVILLE, Texas—Inside a converted Walmart Supercenter about 6 miles from the U.S. border with Mexico, nearly 1,500 young immigrant boys have found their first home in the U.S.

The shelter for immigrant youth in the corner of South Texas opened last year with a capacity of about 1,200. It expanded last month and had fewer than 50 beds to spare on Wednesday afternoon.

For several weeks, the Trump administration has been pursuing the controversial policy of separating parents and children caught crossing into the U.S. illegally, part of its broader effort to reduce the flow of foreigners coming into the U.S. It has been sending the children to temporary foster homes or shelters like this one.

Attorney General Jeff Sessions has begun prosecuting nearly every adult caught crossing the border illegally. He has warned parents that if they don’t want to be separated from their children, they shouldn’t come here illegally.

“You’re going to see a lot of kids,” Juan Sanchez, president and chief executive of Southwest Key Programs, which runs the Casa Padre shelter, told a group of reporters touring the facility Wednesday. “This has been a time of getting a lot of kids really fast.”