 On 13 April 1941 , Hitler issued Directive No. 27 , including his occupation policy for Greece . He finalized jurisdiction in the Balkans with Directive No. 31 issued on 9 June . Mainland Greece was divided between Germany , Italy and Bulgaria , with Italy occupying the bulk of the country ( see map opposite ) . German forces occupied the strategically more important areas of Athens , Thessaloniki , Central Macedonia and several Aegean islands , including most of Crete . They also occupied Florina , which was claimed by both Italy and Bulgaria . Bulgaria , which had not participated in the invasion of Greece , occupied most of Thrace on the same day that Tsolakoglou offered his surrender . The goal was to gain an Aegean Sea outlet in Western Thrace and Eastern Macedonia . The Bulgarians occupied territory between the Struma river and a line of demarcation running through Alexandroupoli and <unk> west of the Evros River . Italian troops started occupying the Ionian and Aegean islands on 28 April . On 2 June , they occupied the Peloponnese ; on 8 June , Thessaly ; and on 12 June , most of Attica . The occupation of Greece — during which civilians suffered terrible hardships , many dying from privation and hunger — proved to be a difficult and costly task . Several resistance groups launched guerrilla attacks against the occupying forces and set up espionage networks . 
