Gunmen Force Troops Off Border Watch - washingtonpost.com
The Associated Press Friday, January 5, 2007; 7:34 AM
TUCSON, Ariz. — National Guard troops at an observation post near the Mexico border were forced to flee a group of armed people, who later ran into Mexico, authorities said.
The troops, who are not allowed to apprehend illegal border crossers, withdrew safely and no one was injured, said National Guard Sgt. Edward Balaban.
Sgt. Balaban was also quoted in an earlier story [Guard's hands-off approach tightens border security | 10.21.2006] which said
They aren't allowed to apprehend illegal entrants or leave their post.
Of course, that means they can't "leave their post" in a forward direction. Running away is okay.