The invasion was preceded by weeks of intense resistance activity. Coordinated with the massive bombardments of the Transportation Plan and supported by the SOE and the OSS, partisans systematically sabotaged railway lines, destroyed bridges, cut German supply lines, and provided general intelligence to the allied forces. The constant harassment took its toll on the German troops. Large remote areas were no-go zones for them and free zones for the maquisards so-called after the maquis shrubland that provided ideal terrain for guerrilla warfare. For instance, a large number of German units were required to clear the maquis du Vercors, which they eventually succeeded with, but this and numerous other actions behind German lines contributed to a much faster advance following the Provence landings than the Allied leadership had anticipated.