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.

The U.S. military will send 1,500 additional active-duty troops to the border with Mexico, the White House said on Wednesday, just two days after President Donald Trump signed an executive order on immigration.

The Pentagon will begin deploying as many as 1,500 active duty troops to help secure the southern border in the coming days, officials said.