In mid-March 1941 III./KG 3 staged down through France to Münchendorf, Austria and carried out training exercises from 27 to 29 March 1941. The group had 28 Dorniers, with 26 combat ready and three Junkers Ju 88s. It placed under the command of Luftflotte 4 under the command of Alexander Löhr until 5 April. The group supported the invasion of Yugoslavia, and was involved the bombing of Belgrade on 6 April. 102 Do 17s, carrying 18 SC 50 kg (110 lb) fragmentation bombs, and 2 AB 36 cluster bombs attacked the capital. Some 82 Do 17s remained operational after the first day, with only one reported loss, a KG 3 machine. Another sources states two; both from 8 "staffel". The campaign terminated on 18 April, with a swift Axis victory.