<p>Acting Defense Secretary Patrick Shanahan, accompanied by the Joint Chiefs chairman, Gen. Joseph Dunford, was visiting a border site called Monument Site 3 near El Paso, Texas, where National Guard troops are working with Customs and Border Protection. Shanahan and Dunford were getting a look at vehicles used for border surveillance. The Department of Homeland Security has requested Pentagon help in operating cameras mounted on the vehicles. Later, the officials planned to fly over two border control sites farther west. These sites are on a list of high-priority projects DHS submitted to Shanahan on Friday to support its request for money to pay for construction of roads, replacement of vehicle barriers and dilapidated pedestrian fencing, and installation of lighting. The pedestrian fencing would include detection systems that could alert border patrol agents when someone is attempting to damage or break through the fencing. The money would come from the Pentagon's drug interdiction programs.</p>