Homeland Security Secretary Kristi Noem said the directive came directly from President Trump, under the expectation the dark paint will discourage migrants to climb the wall by making it unbearably hot under the desert sun.

WASHINGTON — Homeland Security Secretary Kristi Noem said Tuesday that the entire border wall along the southern border with Mexico is going to be painted black to make it hotter and deter illegal immigration — and she credited President Trump with the idea.