Federal officials turned away a group of Oregon congressmen and the governor after they asked for a tour of a Portland facility that houses immigrant children.

Gov. Kate Brown, U.S. Sen. Jeff Merkley, U.S. Sen. Ron Wyden, and U.S. Rep. Suzanne Bonamici, all Democrats from Oregon, asked the Office of Refugee Resettlement for permission to tour the Morrison Child & Family Services building where immigrant children are being held.

The federal office denied the request, saying that a federal field specialist needed to be on site to answer questions but was not available. The Oregon officials said that the nonprofit that has a contract to run the facility had cooperated and expressed a willingness to allow the delegation to tour the building.

"It is clear that there is no reasonable explanation as to why the tour can't take place," the group said in a statement. "This is a Trump Administration strategy to prevent members of Congress from being able to enter these facilities and check on the condition of the children. We support the administration's recent efforts at family reunification, but that is not an excuse to refuse to allow Congressional oversight over a facility under contract with the federal government. This is unacceptable."

Merkley and Wyden have co-sponsored a bill that would require the U.S. Department of Homeland Security and U.S. Health and Human Services to allow members of Congress to tour facilities that hold immigrant children within 24 hours of requesting access.

The denial comes a month after Merkley live-streamed his failed visit to a detention center for immigrant children in Texas. The social media post went viral, and marked the start of a higher level of scrutiny of the Trump administration's immigration policies.