Under the leadership of the new Bulgarian pro-Soviet government, four Bulgarian armies, 455,000 strong in total, were mobilized and reorganized. By the end of September, the Red Army 3rd Ukrainian Front troops were concentrated at the Bulgarian-Yugoslav border. In the early October 1944 three Bulgarian armies, consisting of around 340,000-man, together with the Red Army reentered occupied Yugoslavia and moved from Sofia to Niš, Skopje and Pristina to blocking the German forces withdrawing from Greece. In Macedonia the Bulgarians operated in conjunction with the fighters of the MNLA, but this cooperation did not proceed without difficulties. From 8 October to 19 November, the "Stratsin-Kumanovo operation" was held and Kratovo, Kriva Palanka, Kumanovo and Skopje were taken. At the same time the "Bregalnitsa-Strumica operation" was led, and the Wehrmacht was driven from the villages of Delchevo, Kočani, Stip, Strumica and Veles. In parallel, the "Kosovo operation" was also taking a place, aiming to expel the German forces from Kosovo. Southern and Eastern Serbia, Kosovo and Vardar Macedonia were liberated by the end of November. The 3rd Ukrainian Front in collaboration with the People's Liberation Army of Yugoslavia and Bulgarian People's Army carried out the Belgrade Offensive. The 130,000-strong Bulgarian First Army continued to Hungary, driving off the Germans, while the rest moved back to Bulgaria. On a series of maps from Army Group E, showing its withdrawal through Macedonia and Southern Serbia, as well as in the memoirs of its chief of staff, there is almost no indication of Yugoslav Partisan units, but only Bulgarian divisions. Despite these facts, the contribution of Bulgarian troops is still much debated in the Republic of Macedonia for political reasons.