U.S. officials say active duty military troops are arriving in El Paso, Texas, and in San Diego on Thursday evening.

Troops have assisted at the border before and will be limited to support roles unless the administration invokes the Insurrection Act.

Hours after Trump’s inauguration, his administration canceled appointments allowing migrants to enter the U.S. to request asylum, leaving many of them stranded on the U.S.-Mexico border.

Immigration officials are already taking action along the Texas-Mexico border. The American Civil Liberties Union has already filed at least one lawsuit.

Mexico was raising sprawling tents on the U.S. border Wednesday as it braced for President Donald Trump to fulfill his pledge to reverse mass migration