Trump visits the border wall

President Donald Trump talks with a U.S. Customs and Border Protection (CBP) Border Patrol Agent while participating in a tour of U.S.-Mexico border wall prototypes near the Otay Mesa Port of Entry in San Diego, California, March 13, 2018....more

President Donald Trump's motorcade drives past police officer in riot gear as he leaves the border in San Diego, California. REUTERS/Mike Blake

Trump supporters hug after President Donald Trump's motorcade drove past them in San Diego, California. REUTERS/Mike Blake

President Donald Trump tours border wall prototypes. REUTERS/Kevin Lamarque

Homeland Security Secretary Kirstjen Nielsen pauses while speaking next to President Donald Trump following a tour of border wall prototypes in San Diego, California. REUTERS/Kevin Lamarque

President Donald Trump speaks while participating in a tour of border wall prototypes. REUTERS/Kevin Lamarque

People hold signs reading "No to the wall, Trump," and "Trump, we are not enemies of the USA" during a protest near the prototypes in Tijuana, Mexico. REUTERS/Edgard Garrido

U.S. police officers stand on top of trucks parked between the prototypes of the border wall and the current border fence, in Tijuana, Mexico. REUTERS/Edgard Garrido

U.S. Army veteran Hector Lopez protests in front of the current border fence in Tijuana, Mexico. REUTERS/Edgard Garrido

U.S. Customs and Border Protection (CBP) Border Patrol Agents sit on horseback in San Diego, California. REUTERS/Kevin Lamarque

President Donald Trump drives past supporters and protesters as he arrives at the border to view prototypes. REUTERS/Mike Blake

President Donald Trump participates in a tour of border wall prototypes. REUTERS/Kevin Lamarque

Activists and community groups hold a rally to condemn the visit of President Donald Trump to California in San Diego. REUTERS/Mike Blake

Activists and community groups hold a rally to condemn the visit of President Donald Trump to California in San Ysidro. REUTERS/John Gastaldo

People hold signs during a protest while standing in front of the current border fence in Tijuana, Mexico. The sign on the right reads "Trump, walls can be jumped over". REUTERS/Edgard Garrido

Journalists gather on the roof of a house next to the current border fence in Tijuana, Mexico. REUTERS/Edgard Garrido

U.S. border patrol stand on top of a hill and near the border between the U.S. and Mexico, as seen from Tijuana, Mexico. REUTERS/Edgard Garrido

A Mexican federal police officer peeks through a hole in the border fence between Mexico and the U.S. in Tijuana, Mexico. REUTERS/Edgard Garrido

People hold signs reading "Trump, we will not pay for the wall" and "Trump, stop the mass deportations" near the border fence in Tijuana, Mexico. REUTERS/Edgard Garrido

Mexican federal police stand guard near the prototypes of President Donald Trump's border wall, seen behind the current border fence, in Tijuana, Mexico. REUTERS/Edgard Garrido