The entire US-Mexico border wall will be painted black to make it hotter and harder to climb, Homeland Security Secretary Kristi Noem has said, crediting the idea to Donald Trump.
While domestic detentions and deportations have been the primary focus of the current immigration crackdown, Trump's policy bill passed earlier this summer also allocated $46m (£34m) for additional wall construction.
About a half mile (0.8km) of wall is going up each day along the nearly 2,000 mile (3,218km) border, according to Noem.
The number of border crossings has plummeted in recent months, and the Trump administration says sweeping arrests and detentions are acting as a deterrent to illegal migration.
Speaking to reporters along a section of the border in New Mexico, Noem said on Tuesday that the black paint was "specifically at the request of the president".
