A member of United Constitutional Patriots New Mexico Border Ops militia team monitors the US-Mexico border in Anapra, New Mexico on March 20, 2019. - The militia members say they will patrol the US-Mexico border near Mt. Christo Rey, "Until the wall is built." In recent months, thousands of Central Americans have arrived in Mexico in several caravans in the hope of finding a better life in the United States. US President Donald Trump has branded such migrants a threat to national security, demanding billions of dollars from Congress to build a wall on the southern US border. (Photo by Paul Ratje / AFP)