The Pentagon will begin deploying as many as 1,500 active duty troops to help secure the southern border in the coming days, U.S. officials said Wednesday, putting in motion plans President Donald Trump laid out in executive orders shortly after he took office to crack down on immigration.

Trump signed an executive order declaring a national emergency at the U.S.’s border with Mexico, allowing the National Guard and military personnel to be sent to the border. The troops are being sent there to help Customs and Border Protection’s work in the area,