The Defense Department is expanding its border role with a new military zone near Yuma, aiming to boost surveillance as crossings continue to fall.

US Department of Defense expands militarised zone along Texas border - The Air Force has stated its readiness to immediately install warning signs prohibiting entry into the zone

SANTA FE, N.M. (AP) — The Department of Defense is expanding a militarized zone along the southern U.S. border where troops are authorized to detain people who enter for possible federal prosecution on charges of trespassing in a national defense area.