During World War II, the OVRA was used by Mussolini to control resistance groups in the Balkans (Tito's National Liberation Army especially) prior to the 1943 armistice and withdrawal. In 1943, with the Allied invasion of Italy, the OVRA began to recruit double agents to infiltrate the British SOE, but these efforts failed to stop Mussolini's ouster. With the establishment of the Italian Social Republic in northern Italy, many OVRA agents flocked to this state led by Mussolini, fighting until Mussolini was executed by Italian partisans on April 28, 1945.