In March, the pro-German Yugoslav government was toppled. A furious Hitler ordered the attack to be expanded to include Yugoslavia. Operation Marita commenced on 7 April. The Luftwaffe committed StG 1, 2 and 77 to the campaign. The Stuka once again spearheaded the air assault, with a front line strength of 300 machines, against minimal Yugoslav resistance in the air, allowing the Stukas to develop a fearsome reputation in this region. Operating unmolested, they took a heavy toll of ground forces, suffering only light losses to ground fire. The effectiveness of the dive bombers helped bring about Yugoslav capitulation in ten days. The Stukas also took a peripheral part in Operation Punishment, Hitler's retribution bombing of Belgrade. The dive bombers were to attack airfields and anti-aircraft gun positions as the level bombers struck civilian targets. Belgrade was badly damaged, with 2,271 people killed and 12,000 injured.