Sen. Jeff Merkley (D-OR) said that he saw undocumented children in cages sleeping on thin space blankets on a concrete floor at a border processing facility. He was then barred from entering another immigrant detention center, he told CNN Monday in an interview.

“They have big cages made out of fencing and wire and nets stretched across the top of them so people can’t climb out,” Merkley told CNN’s Alisyn Camerota of the McAllen border patrol station in Texas he toured on Sunday. “It’s just a concrete floor and people are being given these space blankets to sleep on. A space blanket is…the equivalent of foil. So obviously a very uncomfortable situation to be in.”

Merkley added that when he inquired about the draconian living conditions, he was given “generic” answers: “this is what’s required for security, this is what’s required for control.”

Later, when he attempted to tour an Office of Refugee Resettlement facility in Brownsville, Texas, where migrant children were being held, he was barred and police were called.

“When my team called, they were told it’s the policy not to admit anyone into these centers and we would not be allowed to enter it,” Merkley said. “I conveyed, or my team conveyed, that I was going down to visit the border and see what was going on and I would try to come by and visit and hope that they rethought their position but obviously they didn’t.”

White House Deputy Press Secretary Hogan Gidley fired back in a statement.

“Senator Merkley is irresponsibly spreading blatant lies about routine immigration enforcement while smearing hardworking, dedicated law enforcement officials at ICE and CBP,” he said. “He voted against closing the “catch-and-release” loopholes used by child smugglers, and his reckless open borders policies are responsible for the permanent separation of thousands of American families who have been forced to bury their loved ones.

“No one is taking a public safety lecture from Sen. Merkley, whose own policies endanger children, empower human smugglers and drug cartels, and allow violent criminal aliens to flood into American communities,” he continued.

Merkley made the trip to follow up on the White House’s new “zero tolerance policy” that involves separating undocumented parents from their children when they are apprehended at the border, a policy that has earned attention and criticism as it becomes clear that federal agencies have lost track of some of the children.

“These are families that have gone through traumatic experiences abroad and we’ve always treated such families very graciously as they waited adjudication of their case,” Merkley said. “Now they’re being treated in an enormously cruel fashion, a fashion that rips children out of the arms of their parents, sends them off to places unknown while the parents are locked up.

“This is very, very traumatic for the children, so I wanted to be able to visit the facility where apparently upwards of 1,000 children are being held in that massive building, a former Walmart, and the federal government, President Trump and team, Attorney General Sessions, homeland security, they do not want members of Congress or the public to know what’s going on,” he continued.

Watch part of the interview below: