By Ted Hesson, Alexandra Ulmer WASHINGTON/PIEDRAS NEGRAS, Mexico (Reuters) -Newly sworn-in U.S. President Donald Trump said on Monday he will declare illegal immigration at the U.S.-Mexico border a national emergency,

WASHINGTON - 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.

Migrant shelters in Tijuana - located across the border from San Diego, California - are bracing for a possible surge in the influx of migrants should US President Donald Trump carry out his mass deportation plan.

As Chicago prepares for the possibility of mass immigration raids on Tuesday, a lot of questions remain. Deportation expert and Northwestern University professor Jacqueline Stevens join

Tom Homan, Trump's border czar, has described what the operation might look like and who could be involved in immigration enforcement.

Trump has vowed that mass deportation will be a day-one priority, saying he has “no choice” but to deport anyone who is in the U.S. illegally.