On the same day Bulgarian forces prepared to cross the border and Field Marshal Mackensen received a telegram from the new Chief of the German General Staff von Hindenburg informing him that German and Austro-Hungarian build up in Transylvania would be completed no sooner than the second half of September while the forces that were already deployed would be able only to defend against the advancing Romanians until then. Von Hindenburg and General Zhekov confirmed the orders of the Bulgarian Third Army to advance into Dobrudja in order to draw and defeat as many Romanian and Russian forces as possible, de facto placing the burden of the first Central Powers major offensive during the opening stages of the war on Field Marshal Mackensen, General Toshev and their forces. A day earlier the commander of the army group and the commander of the Third Army had met in Gorna Oryahovitsa to finalize the offensive plan. General Toshev, who had more up to date intelligence regarding the strength of the opposing forces and their fortification, convinced the field marshal to commit the main forces for an attack of the Tutrakan fortress first, instead of attacking both it and Silistra as was originally noted in the army group directive from 28 August. The two also agreed to deploy troops to cover Silistra against Romanian flanking attacks on the main forces and insure sufficient reserves to hold the right flank of the army around Dobrich. All the troops detailed for the defense of the Danube were placed under the direct control of the army group headquarters and the Ruse Fortified Area was placed under the command of Colonel Kaufman. For the offensive General Toshev kept direct control over the field troops of the army consisting of the 1st, 4th and 6th Infantry Divisions, 1st Cavalry Division, the Varna Fortified Area and could also expect to be joined by 1 German and 5 Bulgarian battalions from Colonel Kaufman's forces. Thus by 1 September the attacking forces managed to concentrate 62 infantry battalions, 3 pioneer battalions, 23 squadrons and 55 batteries along the Dobrudja frontier. Facing the Bulgarian Third Army from the river Olt to the Black Sea coast was the Romanian Third Army commanded by General Mihail Aslan with a total of 149,028 men in 104 battalions and 44 squadrons supported by 235 machine guns and 131 batteries. However these forces had to cover a long front and only some 72,000 men in 55 battalions and 9 squadrons supported by 173 machine guns and 67 batteries were located in Dobrudja.