Soon after FF's seizure of power, the partisans became the first forces to resist the attempted return of the Wehrmacht in Bulgaria on its western and northwestern border. Bulgarian partisans also participated in the liberation from Nazi occupation of some towns and villages in Yugoslavia and Greece. After 9 September and prior to Bulgaria's army joining the Allies' fight against the Axis, former partisans were placed in key positions in the Bulgarian military to ensure its loyalty. Former partisans also built up the new People's Militia, which replaced the Bulgarian police. They allegedly participated in mass retaliation which took the lives of thousands of former civil servants, policemen and gendarmes.