frequent, as were Yugoslav charges against Bulgaria for fostering the Internal Macedonian Revolutionary Organization (IMRO), a nationalist group that used violence, in Yugoslavia. Macedonian agitation against Serbian rule culminated (1934) in the assassination of King Alexander of Yugoslavia by a Bulgarian nationalist at Marseille. World War II In World War II, following the Italian invasion on 28 October 1940, Greece repelled the initial Italian attack and a counter-attack in March 1941. When the German invasion, known as Operation Marita, began on 6 April, the bulk of the Greek Army was on the Greek border with Albania, then a vassal of Italy, from which the Italian troops had attacked. German troops invaded from Bulgaria, creating a second front. The Greek army found itself outnumbered in its effort to defend against both Italian and German troops. As a result, the Metaxas defensive line was quickly overrun by the Germans, who then outflanked the Greek forces at the Albanian border, forcing their surrender. Greece's territory was divided into occupation zones run by the Axis powers, with the Germans proceeding to administer the most important regions of the country themselves, including Thessaloniki. Other regions of the country were given to Germany's partners, Italy and Bulgaria. Thrace and eastern Macedonia were occupied (1941–44) by Bulgaria, which sided with the Axis Powers. The occupation ruined the Greek economy and brought about terrible hardships for the Greek civilian population. At the same time the Greek Resistance was formed in Macedonia as well as in the rest of Greece. These resistance groups launched guerrilla attacks against the occupying powers, fought against the collaborationist Security Battalions, and set up large espionage networks. The Greek Resistance killed 21,087 Axis soldiers (17,536 Germans, 2,739 Italians, 1,532 Bulgarians) and captured 6,463 (2,102 Germans, 2,109 Italians, 2,252 Bulgarians), for the death of 20,650 Greek partisans and an unknown number captured. Greek Civil War Much of the Greek Civil War was fought in Macedonia. The Communist Party of Greece or KKE and the Democratic Army of Greece or DSE were heavily established in Macedonia. The National Liberation Front was established by Slavic speakers who associate themselves with Yugoslavia who resided in Greece, to assist with the war effort, in return for minority status recognition and rights. However, when the DSE lost the Greek Civil War thousands of people who fought for the Communist side fled Greece, taking thousands of ethnic Macedonian children from the