For several years the US Army has been funding various R&D efforts under the general heading of "STTW" or "See Through The Wall". Among the most promising technologies is that of ultra-wideband radar (UWB). There is no doubt that UWB can detect people in buildings, the real questions are "at what range" and if it can be done under 'battlefield' conditions. It is possible that that the US has fielded a relatively short range system for UAV use. The simplest UWB STTW systems detect a human heartbeat, acting like a 'stud finder' for an infantryman behind a wall or door. The most sophisticated provide 3-d images of the scanned field, including people (and their insides).

I won't bore the reader with a technical explanation (which I am barely qualified to give), but UWB is already being used to do some amazing things.. For example, a system mounted in a truck can be driven over a bridge and image the rebar and interior features of the concrete. A key limitation in the past has been the huge computer processing time needed to process the data. That problem is being addressed by both faster computers and more efficient algorithms. Indeed, for an example of published work take a gander at:

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Here is the important question, IMHO --- forget about Iraq. .What happens when the government "brings this technology home"? It can ultimately provide the ability to not only "see" through wall, but to rapidly scan huge volumes for specific items. A device designed to detect firearms hidden in a shipping container, for example, could instead be used to scan houses.... Just something to think about..