Defense Secretary Pete Hegseth visited the newly created New Mexico National Defense Area on Friday to meet with service members assigned to Joint Task Force Southern Border.
“This is Department of Defense property,” Hegseth said. “Any illegal [attempt] to enter that zone is entering a military base — a federally protected area. You will be detained. You will be interdicted by U.S. troops and border patrol working together.”
Hegseth held a sign in English and Spanish indicating the property’s protected status. The signs state that the area is under U.S. military jurisdiction and warn that trespassers will be detained.
“You’ve got signs like this one all across the border wall facing into Mexico — clear English, clear Spanish,” he said.
Millions of people crossed the U.S.-Mexico border over the past four years, Hegseth said. Since January, the department has stepped up efforts to curb illegal crossings.
A soldier with Joint Task Force Southern Border provides surveillance over the Santa Teresa sector of the southern border near Santa Teresa, N.M., April 12, 2025. © Army Pfc. Sean Hoch
Initial deployments earlier this year included 1,600 active-duty Marines and soldiers joining the 2,500 reservists who had already been mobilized.
In early March, the department sent a Stryker brigade combat team and a general support aviation battalion to the southwestern border to accelerate President Donald J. Trump’s directive to bolster military support in securing the border.
Those units were equipped with wheeled vehicles and aviation assets to support mobility and surveillance. In late March, service members assigned to JTF-SB were authorized to conduct patrols — a shift from the previously static role of detection and monitoring. Last week, the Defense Department assumed jurisdiction from the Department of the Interior over 109,651 acres of federal land along the U.S.-Mexico border.
The area was officially designated the “New Mexico National Defense Area,” April 18, 2025, following a general order signed by the Secretary of the Army to make that NDA part of the existing Fort Huachuca, an Army installation in nearby Arizona. According to the DOI, the agreement for the land transfer is three years.
The transfer of jurisdiction and the creation of the NMNDA was directed by the president as a way to strengthen the authority of service members already participating in border control efforts as part of JTF-SB.
Troops have been working alongside Customs and Border Protection since January to seal the southern border. However, the kind of work they can do there has been limited by federal law. While service members could assist in identifying border crossers, for instance, only CBP personnel could apprehend them.
But now, federal troops participating in JTF-SB, and who are operating on the NMNDA, can temporarily detain trespassers until an appropriate law enforcement entity can assume custody.
Defense Secretary Pete Hegseth talks with two soldiers in New Mexico with Joint Task Force Southern Border, April 25, 2025. © DOD Screen Capture
Service members can now also conduct cursory searches of trespassers to ensure the safety of U.S. service members and DOD property, conduct crowd control measures as necessary, and provide emergency medical support to trespassers to prevent the loss of life, limb or eyesight.
“Through these enhanced authorities, U.S. Northern Command will ensure those who illegally trespass in the New Mexico National Defense Area are handed over to Customs and Border Protection or our other law enforcement partners,” said Air Force Gen. Gregory Guillot, Northcom commander. “Joint Task Force Southern Border will conduct enhanced detection and monitoring, which will include vehicle and foot patrols, rotary wing and fixed surveillance site operations.”
Getting control of the border was at the top of the president’s to-do list on the day he took office. Hours after his inauguration, he signed a document declaring a national emergency at the southern border and said America’s sovereignty was under attack.
“Our southern border is overrun by cartels, criminal gangs, known terrorists, human traffickers, smugglers, unvetted military-age males from foreign adversaries, and illicit narcotics that harm Americans,” the president wrote.
In the same document, the president said the Department of Homeland Security and the U.S. armed forces must seal the border.
Within days of that order, U.S. troops were already heading down south to carry out the president’s directives. On Friday, Northcom directed JTF-SB to carry out that mission alongside CBP.
“For too long, our southern border was poorly equipped and understaffed, and our warfighters were restricted from doing their jobs,” Hegseth said on Friday via social media. “We will secure our southern border and have 100% operational control.”
