The Pentagon said Wednesday it has begun deploying 1,500 active-duty troops to the southern border, putting in motion plans President Trump laid out in executive orders shortly after he took office to crack down on immigration.

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.