U.S. Border Patrol Chief Mike Banks, who attended the event with Noem, said the paint would also help deter rust.

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.

U.S. Border Patrol Chief Mike Banks, who attended the event with Noem, said the paint would also help deter rust.