The first serious air raid on Gibraltar came at 02.00 on 18 July, when two unidentified aircraft bombed the slopes of the Rock, causing some fatalities. The attack was thought to be by the Vichy French Air Force in retaliation for the British attack on the French fleet at Mers-el-Kebir on 3 July (Operation Catapult), which had been carried out by Force H from Gibraltar. On 21 August the AA defences brought down a Savoia-Marchetti SM.79 bomber during a raid by the Italian "Regia Aeronautica". On 24 and 25 September waves of Vichy bombers attacked Gibraltar again in retaliation for the British and Free French attack on Dakar (Operation Menace), and caused considerable damage. Several of these bombers were shot down by the combined AA fire. On other occasions the guns fired at single Italian reconnaissance aircraft, known to the garrison as 'Persistent Percy'.