The Pentagon’s Transportation Command will use military aircraft to send more than 5,000 undocumented immigrants from San Diego and El Paso, Texas, who are detained by Customs and Border Protection, Acting Defense Secretary Robert Salesses said in a statement. The troops also will assist in building new border fences and barriers.

The deployment signals the military’s increased role in a much more aggressive immigration policy under the second Trump administration.

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

The Pentagon will send 1,500 active-duty troops to the southwestern border by the end of the month, a Defense Department official said on Wednesday, helping to fulfill one of President Trump’s main goals to stem the flow of migrants into the United States.