 Putnik reasoned that Austro @-@ Hungarian supply lines would become overstretched as their forces pressed deeper into Serbia while the Serbs would continue to hold the railheads in the Serbian interior . On 10 November , he ordered a general retreat from the Jadar and withdrew the Serbian 2nd Army to Ub and positioned the 1st and 3rd armies north and west of Valjevo . Meanwhile , the Užice Army took up positions to defend the town from which it took its name . The Austro @-@ Hungarians pressed after the Serbs , hoping to capture the Obrenovac – Valjevo railroad . Clashes ensued and the Serbian Army managed to prevent the Austro @-@ Hungarians from taking the railroad for a time . It quickly became clear to Putnik that he had underestimated the Austro @-@ Hungarians , who managed to bring their heavy artillery through the muddy Serbian country roads . They established firing positions on the Serbian side of the Drina and began targeting the Serbian Army , which suffered heavy casualties . Morale plummeted amongst the Serbs , who were already significantly demoralized due a lack of cold @-@ weather clothing and ammunition and exhausted by the long retreat towards the Serbian interior . Putnik realized that his forces would need to regroup if they were to provide any effective resistance to the Austro @-@ Hungarians . He ordered that Valjevo be abandoned and had the Serbian Army take up positions on the Kolubara . The retreat towards the river was long and excruciating , with the Serbs being forced to destroy all bridges and telephone lines so that they would not fall into Austro @-@ Hungarian hands . The Serbian Army also abandoned most of its heavy equipment to speed up the withdrawal . Seeing that the situation was critical and that Serbian forces were lacking artillery , ammunition and supplies , Pašić sought the help of the Triple Entente . He sent a telegram to his envoys abroad , which read : " Urgent help is required . Beg and plead . " France provided the Serbs with munitions and supplies . Representatives of Russia and the United Kingdom " expressed understanding " , but those countries failed to deliver weapons and munitions . 
