After the victory at the Battle of Kirk Kilisse the Bulgarian First and Third armies advanced to the south in pursuit of the Ottoman Eastern Army and cut the line of communication between Adrianople and Constantinople. The 3rd Balkan Division was ordered by the commander of the First Army to remain around Adrianople, to protect the army's rear and cooperate with the Second Army. With the fortress now almost completely isolated, its commander Shukru Pasha ordered a new attack on 16 October with 18 infantry battalions against the Bulgarian 3/8, 1/9 and 2/9 infantry brigades but it soon failed and the Turkish troops retired to their main defensive line. On the same day with their main forces engaged at the Lule Burgas the Bulgarians decided to complete the encirclement of the fortress. Two brigades of the 9th Division were sent to assist the Third Army while their place was taken by the newly formed 11th Mixed Infantry Division. By 26 October the fortress was completely cut off but the Bulgarian lines were overstretched and in held by very few troops on many places. The Bulgarian High Command used a previously reached agreement with Serbia, that allowed the deployment of Serbian forces in Eastern Thrace, to reinforce the Bulgarians with two divisions of the Serbian Second Army. By early November the last of the Serbian forces had arrived. With the attention of the Bulgarians focused on the Çatalca line a new attempt by the Ottomans to break the siege was repulsed on 29 and 30 October. Until the first armistice was concluded the Second Army limited its operations to tightening the encirclement and shelling the fortress in order to reduce the morale of its defenders.