The U.S. military has been officially authorized to detain illegal immigrants along part of the southern border, U.S. Northern Command announced Monday.
This move marks a major step in the Trump administration’s border crackdown. Troops are now allowed to temporarily detain and search individuals suspected of illegal entry within the newly established New Mexico National Defense Area (NMNDA). The 170-mile strip is now considered part of Fort Huachuca, placing it under full military control.
“This is about protecting our country and supporting our law enforcement partners in a lawful, constitutional manner,” said Gen. Gregory Guillot, Commander of U.S. Northern Command. “Joint Task Force-Southern Border will conduct enhanced detection and monitoring, including patrols on foot, in vehicles, and through aerial surveillance to identify and respond to illegal activity.”
The Department of Defense confirmed that service members under Joint Task Force-Southern Border began conducting increased detection efforts in March. Under the new authorities, these troops can now detain trespassers on military-controlled land until they are transferred to Customs and Border Protection or other law enforcement agencies. They are also permitted to conduct limited searches and carry out crowd control measures if necessary for safety and security.
Troops may also be asked to install temporary fencing, barriers, and signs as directed by senior military leadership.
The shift comes after President Trump issued an order on April 11 transferring control of the Roosevelt Reservation—a border-adjacent land strip in New Mexico—from the Department of the Interior to the Department of Defense for a three-year period.
This legal maneuver allows military personnel to carry out functions that would normally be restricted under the Posse Comitatus Act, which bars the military from performing domestic law enforcement duties.
For years, troops deployed to the border under both Republican and Democrat administrations were tasked with logistical and surveillance support—not direct engagement. But with this latest move, the Trump administration has moved to give military personnel a more active role.
White House press secretary Karoline Leavitt confirmed that more than 90 additional miles in Texas are expected to be added to the defense area in the coming weeks, expanding the military’s operational zone even further.
The policy change is expected to bolster efforts to stem the flow of illegal immigration and send a clear message that trespassing on U.S. soil will now meet a more immediate response.