Three Bombardment Groups were allocated to support the Allied invasion of French North Africa in November 1942. They were initially used to carry out low-level attacks against heavily defended targets, incurring heavy losses with poor results, before switching to medium level attacks. By the end of the North African Campaign, the three B-26 groups had flown 1,587 sorties, losing 80 aircraft. This was double the loss rate of the B-25, which also flew 70% more sorties with fewer aircraft. Despite this, the B-26 continued in service with the Twelfth Air Force, supporting the Allied advance through Sicily, Italy and southern France. Air Marshal Sir John Slessor, Deputy Commander-in-Chief Mediterranean Allied Air Forces, wrote of "the astonishing accuracy of the experienced medium bomber groups – particularly the Marauders; I think that the 42nd Bombardment Group in Sardinia is probably the best day-bomber unit in the world." Slessor in fact meant the 42nd Bomb Wing—17th, 319th and 320th Bomb Groups—but a US 'wing' equated roughly to a British 'group', and vice versa.