The Mediterranean U-boat Campaign lasted approximately from 21 September 1941 to 19 September 1944 during World War II. Malta was an active British base strategically located near supply routes from Europe to North Africa. As a result, Axis supply convoys across the Mediterranean Sea suffered severe losses, which in turn threatened the fighting ability of the Axis armies in North Africa. At the same time the Allies were able successfully to keep their North African armies supplied. The Kriegsmarine initially aimed, unsuccessfully, to isolate Malta but later it concentrated its U-boat operations on disrupting Allied landings operations in southern Europe.