A U.S. Border Patrol instructor yells at trainees after their initial arrival at the U.S. Border Patrol Academy on Aug. 2, 2017 in Artesia, New Mexico.

All new agents must complete a months-long training course at the New Mexico facility before assuming their posts at Border Patrol stations, mostly along the U.S.-Mexico border.

Border security was a signature issue of Donald Trump's campaign and President Trump has pledged to add an additional 5,000 agents to the existing Border Patrol force of more than 21,000.