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.

Newly sworn-in U.S. President Donald Trump said on Monday that he would declare illegal immigration a national emergency, send troops to the U.S.-Mexico border, and reinstate his "remain in Mexico" policy as part of a sweeping immigration crackdown.

In line with Trump’s edict, CNN’s Natasha Bertrand, Priscilla Alvarez, Haley Britzky and Oren Liebermann report. They’re expected to beef up existing operations to support Customs and Border Protection,