By September 1944, the Free French forces stood at 560,000 (including 176,500 White French from North Africa, 63,000 metropolitan French, 233,000 Maghrebis and 80,000 from Black Africa). The GPRF set about raising new troops to participate in the advance to the Rhine and the invasion of Germany, using the FFI as military cadres and manpower pools of experienced fighters to allow a very large and rapid expansion of the French Liberation Army. It was well equipped and well supplied despite the economic disruption brought by the occupation thanks to Lend-Lease, and their number rose to 1 million by the end of the year. French forces were fighting in Alsace-Lorraine, the Alps, and besieging the heavily fortified French Atlantic coast submarine bases that remained Hitler-mandated stay-behind "fortresses" in ports along the Atlantic coast like La Rochelle and Saint-Nazaire until the German capitulation in May 1945.