The U.S. southern border has seen a sharp drop in migrant encounters entering between ports of entry at the southern border, according to a CBP source.

U.S. President Donald Trump on Monday signed executive orders declaring illegal immigration at the U.S.-Mexico border a national emergency, designating criminal cartels as terrorist organizations, and targeting automatic citizenship for U.

Trump invoked Article IV, Section 4 of the U.S. Constitution, which obligates the federal government to protect states against invasion, and Article II, asserting his authority to secure the border. The action also relies on provisions in the Immigration and Nationality Act.