The Republican congressman whose district includes more miles of U.S.-Mexico border than any other came out against President Trump’s new executive action ordering the “immediate construction” of a border wall to block undocumented immigrants from entering the United States.

“Building a wall is the most expensive and least effective way to secure the border,” Rep. Will Hurd (R-Tex.) said in a statement late Wednesday.

“Each section of the border faces unique geographical, cultural, and technological challenges that would be best addressed with a flexible, sector-by-sector approach that empowers the agents on the ground with the resources they need.”

Hurd, one of 38 Texans in Congress, represents territory stretching from San Antonio to El Paso, including 800 miles of border. His 23rd District is majority-Hispanic and politically competitive: Hurd won a second term over Democrat Pete Gallego by fewer than 4,000 votes in November.

His comment on Trump’s border wall came amid several days of planned actions on immigration by the new president. Trump signed orders aimed at cracking down on illegal immigration by creating more detention centers, increasing the number of federal border agents and withholding federal funds from cities that do not comply with federal immigration law.

Trump said construction of a wall will take place “as soon as we can physically do it.… I would say in months.”

Hurd, who campaigned on a promise of standing up to Trump and this week called on the new president to release his tax returns, said it is “impossible” to build a physical wall in the rough terrain of his district.

“Big Bend National Park and many areas in my district are perfect examples of where a wall is unnecessary and would negatively impact the environment, private property rights and economy,” Hurd said, advocating for an “intelligence-led approach” to border security.

No member of Texas’s congressional delegation had offered full-throated support of a complete border wall as of Dec. 20, according to a survey by the Texas Tribune.

House Speaker Paul D. Ryan (R-Wis.) said Wednesday night that Congress would appropriate money for the project and explore “different ways of getting Mexico to contribute.”