ABC's Tom llamas from Houston. Reporter: For the first time, a look inside the country's largest facility for undocumented children. We're invited in. No recording devices allowed, no cell phones. So many people have been asking what happens to those children once they're separated from their parents. Well, they're brought here to a facility where they're taken care of by the federal governnt. This is as far as our cameras are allowed to go. You can see it says "Keep out, private property," and this facility is so big it used to be a Walmart super center. These images provided by the government. Nearly 1,500 boys between 10 and 17 years old now live in a converted big box store. We're shown the boys' rooms, meant for four beds, nw with five. Classrooms for civics and English lessons. The kids play video games, pool and foosball, but spend just two hours a day outside. And they're granted just two phone calls a week. The average stay in facilities like this, 56 days. Most of these children crossed illegally, unaccompanied, but facilities like this are now running out of space now that families are being separated. Elected leaders want answers. Senator Jeff Merkley trying to get inside this very center last week. Can you please give me a tour of it? A tour? Reporter: But denied entry. What is your name again, sir? I'm sorry, senator? Senator Jeff Merkley. Reporter: And tonight attorney general Jeff sessions invoking the bible in defense of the administration's hard line immigration policy. You know that the lord told Nehemiah that when he got to come back home to Jerusalem, to build a wall. That's the first thing he told him to do. It wasn't to keep people in, it was to keep bad people out. Reporter: This mother telling us "What is happening is inhumane." Her five-year-old daughter taken from her for days after she illegally crossed the border. She's now worries the little girl may have psychological trauma. Today the white house pressed on the enforcement tactics that have separated more than 700 families. Come on, Sarah, you're a parent. Don't you have any empathy for what these people are going through? They have less than you do. Brian! Guys, come on, settle down. Sarah, come on, seriously. I'm trying to be serious but I'm not going to have you yell out of turn. Tom llamas with us live from Houston. Tom, you said the government is running out of space with these facilities. What's the plan moving forward? Where will they put the children? There are more than 100 facility across the U.S. They're reaching capacity. They'll have to open emergency and temporary shelters. This shelter in Houston may turn into one. This is near the border near el Paso, tent like structures going up. We're being told they can house more than 300 children. They're air conditioned. That's a good thing. The temperatures in El Paso near 99 degrees. Tom thank you. President trump with new praise for north Korean leader