Gibraltar and had the task of maintaining naval superiority and providing a strong escort for convoys to and from the Malta. Malta was from Sicily and one of the first targets of the Italian army and the Regia Aeronautica; the air defence of Malta comprised six obsolescent Gloster Gladiator biplanes. After the first Italian air attacks it became clear that Malta could be defended and in early July, the Gladiators were reinforced by twelve Hawker Hurricane fighters. The Kriegsmarine began operations in the Mediterranean with establishment of the 23rd U-boat Flotilla at a base on Salamis Island in Greece in September 1941. The flotilla was to operate against British supply convoys to Allied forces on Malta and in Tobruk. On 7 December, control of the 23rd Flotilla was transferred from Kernével to Field Marshal Albert Kesselring, Commander in Chief South (OB Süd) in Italy. Additional bases were established in Pola and La Spezia in northern Italy, as more U-boats were sent to the Mediterranean. Bombing and the naval blockade led to food and commodity shortages and rationing was imposed on the inhabitants. Luftwaffe reinforcements in the Mediterranean joined in the bombing but during a lull in early 1942, 61 Supermarine Spitfires were delivered, which very much improved the defensive situation, although food, ammunition, and fuel were still short. Supply runs during lulls in the bombing kept Malta in being but many ships like were damaged too severely to leave. The defence of the island ensured that the Allies had an advantage in the fight to control the Mediterranean and as the garrison recovered from periods of intense bombing, aircraft, submarines and light surface ships resumed attacks on Axis supply ships, leading to fuel and supply shortages for the Axis forces in Libya. Allied reply North Africa During 1941, the British launched several offensives to push back the Axis forces in North Africa. Operation Brevity failed as did Operation Battleaxe but Operation Crusader, the third and larger offensive was launched at the end of the year. Over December 1941 into early 1942, Allied forces pushed the Italian-German forces back through Libya to roughly the limit of the previous Operation Compass advance. Taking advantage of the Allied position, German forces counter-attacked and pushed back the Allies to Gazala, west of Tobruk. As both sides prepared offensives, the Axis forces struck first and inflicted a big defeat upon the Allied forces during the