 On 8 November , the Austro @-@ Hungarians attacked the Serbian 2nd Army near Cer Mountain and came within 1 @.@ 6 kilometres ( 0 @.@ 99 mi ) of the Serbian frontline , entrenching themselves at the foot of the mountain . The 2nd Army was given orders to hold the Austro @-@ Hungarians down for as long as possible and , if its position became untenable , retreat towards the right bank of the Dobrava River and position itself so as to block the approach to Valjevo . Elsewhere , the Austro @-@ Hungarians drove a wedge between the 1st and 3rd Army and forced another Serbian retreat . Later that day , the Serbian Government held a joint session with the Serbian Supreme Command with regard to Serbia 's worsening military position . Putnik stressed that it was critical for Serbia to hold the Kolubara and the towns within its vicinity and suggested that the Serbs make a separate peace with Austria @-@ Hungary if this proved impossible . This notion was rejected by the Prime Minister of Serbia , Nikola Pašić , who urged further resistance to the Austro @-@ Hungarians and threatened the resignation of his government if peace discussions began . The session ended with the Serbian Government and Supreme Command agreeing to fight on . 
