Migrants across the U.S. and Arizona faced the spectre of ICE raids under the new administration of President Donald Trump.

Trump ended use of a border app to allow migrants to enter the country on two-year permits with eligibility to work, canceling tens of thousands of appointments into early February for people stranded in Mexico. Nearly 1 million people entered the U.S. at land crossings with Mexico by using the CBP One app.

ICE has take a spotlight role in the wake of plans in Trump's administration for mass deportations. Here's what you need to know about the agency.