Before Rommel's arrival, Mussolini's invasion of Greece, in October 1940 and the Italian offensive against the British in Egypt the previous month had been a complete disaster. The British had driven the Italian forces back into Libya, and now seemed poised to sweep them out of Africa altogether. The Greek Army had also pushed back the Italians into Italian-occupied Albania, and, while the Greeks hesitated to ask for British troops for fear of German intervention, a few RAF squadrons participated in the operations against the Italians. Hitler was infuriated that the British were now within striking distance to the vital Romanian oil fields of Ploieşti. The Germans postponed their attack on the USSR from 15 May 1941, to the 22 June in order to secure their south-eastern flank. Germany began preparing for Operation Marita, the invasion of Greece via Bulgaria.