CellDAR
I'm guessing that the secret tech the US claim they have is actually the much under-trumpeted CELLDAR technology developed here in the UK.
Put simply, the cell towers are constantly pumping out 900Mhz signals into the ether. When that signal reaches something, it changes slightly, be it a person, building or rock.
Stick a load of monitoring devices around the area and you can quickly establish a baseline of reflected and altered signals, such that when someone does start creeping around later that night - the ether is disturbed and they can be located VERY quickly.
Quick enough for a warplane/rendition flight/hellfire missle to catch up in quick fashion.
And no amount of removing batteries is going to keep the tower tech from sussing you. We can't forget that the taliban are free thinking, smart humans too. Even though they are the devil incarnate, Fact!