Acting Homeland Security Secretary Elaine Duke said Tuesday that the border wall at the Yuma, Arizona sector of the border shows that border walls work, just hours before Trump was set to visit there.

"Our Border Patrol agents have seen firsthand the success of a border wall in Yuma, Ariz. — which serves as a prime example of how investments in personnel, technology and a border wall can turn the tide against a flood of illegal immigration and secure our homeland," Duke wrote in an op-ed for USA Today called "Border walls work. Yuma sector proves it."

Duke said there was chaos at that sector of the border until lawmakers passed a bipartisan bill calling for the buildup of a wall there. She noted that then Sens. Hillary Clinton, Barack Obama, and Joe Biden all supported that bill.

"Yuma sector was one of the first areas to receive infrastructure investments," she wrote.

"We built new infrastructure along the border east and west of the San Luis Arizona Port of Entry in 2006," she added. "The existing fence was quickly lengthened, and we added second and third layers to that fencing in urban areas. Lighting, roads and increased surveillance were added to aid agents patrolling the border."

As a result, she said, Yuma is "more secure" with the wall, and said apprehensions even under relaxed enforcement under President Obama were about one-tenth the levels seen a decade earlier.

She also reiterated Trump's point that enforcement will get tougher under the Trump administration.

"Under Trump, the days of permisos are over," she wrote. "We are a nation that secures its borders and enforces its immigration laws. We are a nation of laws — laws that exist for the safety and security of all our people."

Trump's visit to Yuma will come just a few weeks before Congress returns to wrestle with his request for more money to fund the start of expanded construction of the border wall.