He’s a U.S. Senator. How do they explain keeping him out?

Democratic tried to visit an immigration detention facility in Texas over the weekend, but was soon denied access into the building. This prompted questions about what’s going on behind closed doors at some of the country’s detention facilities amid concerns about the separation of children from their parents who have attempted to cross the border illegally.

Merkley live-streamed his arrival at a detention facility run by the Office of Refugee Resettlement in Brownsville, Texas on Sunday, which he said was housing children who had been separated from their families at the border. During Merkley’s live stream, the senator introduced himself to guards outside the building, identifying himself as a member of Congress and asking for permission to enter. The windows at the facility appeared to be blacked out.

“I was barred entry,” Merkley said. “Asked repeatedly to speak to a supervisor — he finally came out and said he can’t tell us anything. Police were called on us,” he added in a tweet.

“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,” Merkley later told CNN in a phone interview on Monday.