a detached part of the Second Bulgarian Army from the South, the Eleventh army from the north and finally the main forces of the Third Army from the northwest while its XIX Army Corps blocks any Serbian retreat to the west. However, after the fall of Niš the Germans began pulling out some of their forces from the Balkans and the Bulgarian Sixth and Ninth divisions had been slowed by the swollen waters of the Morava and the destruction of its bridges. In these circumstances on 1 November the Central Powers began the Kosovo Offensive. Contrary to the intentions of generalfeldmarschall Mackensen the advance of his army group proved to be difficult and slow due to bad roads, lack of supplies and the cold weather. This allowed the Serbians to gradually retreat in good order further into Kosovo and to concentrate greater forces against the Northern Operations Group of the Second Bulgarian Army in an attempt to break through and join the French and British forces advancing up the Vardar valley. In view of these events on 6 November the 8th "Tundzha" division left the First Army and was placed under the command of the Northern Operations Group while the 6th "Bdin" division was ordered to redeploy around Blagoevgrad and Dupnitsa under the direct control of the Bulgarian high command. The exhausted Serbians failed to achieve their aims and in the face of the continued advance of the Bulgarian forces towards Pristina from the east and the south ordered a general withdrawal . On 10 November the 9th "Pleven" division and the German 101st division entered the town but the successful retreat of the Serbian Army on the right bank of the river Sitnica meant that its attempted encirclement had failed. This ended the second phase of the campaign. After the defeat in Kosovo the remnants of the Serbian Army began its retreat through Albania to the Adriatic coast. The Germans thought that the campaign was over and continued pulling out their troops from the front while the pursuit of the retreating opponent was left mostly to Bulgarian and Austro-Hungarian forces. On 24 November the 3rd "Balkan" division took Prizren and was placed under the command of the First Army. With the end of the campaign a general order for the regrouping of all Bulgarian forces was issued. The 9th division was moved to the Skopje-Prilep area, the 1st "Sofia"