(AP) -- A U.S. senator said Monday he tried to enter a federal facility in Texas where immigrant children are being held, but police were called and he was told to leave.
The attempt late Sunday by Sen Jeff Merkley of Oregon came amid a national debate over the practice of separating families caught crossing the border illegally.
Attorney General Jeff Sessions recently announced a "zero-tolerance policy" against all people crossing the border illegally. More children are expected to be separated from their parents as a result.
"The administration has started ripping these children out of the arms of their parents," Merkley said in a telephone interview. "That is completely outside the soul of our nation, where virtually all of us have family history, in one branch or another, where somebody fled persecution to come to the U.S."
Merkley said he was able to enter another facility used for processing migrants and run by the Department of Homeland Security. He said he saw men, women and children crowded in cages.
"It reminds me a little bit of a dog kennel, constructed of cyclone fencing," Merkley said. Some of the areas contained men, while others had only women and some had women holding children, he said.
Merkley was accused of grandstanding by Victoria Palmer, a spokeswoman for the Department of Health and Human Services' Administration for Children and Families.
It was out of concerns for "the safety, security and dignity of the children" that Merkley was barred from entering the Brownsville facility, Palmer said in an email.
"No one who arrives unannounced at one of our shelters demanding access to the children in our care will be permitted, even those claiming to be U.S. senators," the statement said.
Through a contractor, the agency is caring for the children being held in a former Walmart with blacked-out windows in Brownsville, a city along the Mexico border.
The Department of Health and Human Services says it operates over 100 shelters in some 17 states, and that children spend an average of 51 days in them.
Merkley live-streamed on Facebook his attempt to visit the Brownsville facility. He said he and the press should be able to see conditions inside.
"Every American citizen has a stake in how these children are being treated and how this policy is being enacted," Merkley said in the video.
In Brownsville, a supervisor emerged from the building and said he wasn't allowed to make any statement. He gave the senator a phone number of the public affairs office in the U.S. Department of Health and Human Services in Washington.
Meanwhile, Brownsville police arrived and asked Merkley for his name and birth date. Merkley provided the information and then tried to explain to the officer why he had come to the facility.
"The attorney general's team, and the Office of Refugee Resettlement, they don't want anyone to know about what's going on behind these doors," Merkley told the police officer.
Sen. Bob Menendez, a New Jersey Democrat, said on Twitter that his team was also barred from a migrant facility where families were being separated. He said the federal government's actions were "outrageous" and called for an explanation from Secretary of Homeland Security Kirstjen Nielsen.
Palmer said there's a "process" for entering such a facility that Merkley should follow "to make headway on this important issue, rather than just headlines."
Merkley said his office was told earlier it would take weeks to have a visit authorized, and that he suspected it would be stage-managed "to look wonderful."
By midday Monday, Merkley's video had over 1 million views on Facebook.