 The Austro @-@ Hungarian base at Zemun was briefly evacuated due to a Serbian counterattack in September . On 28 September , Körös , along with the monitor SMS Temes , a patrol boat and a minesweeper , broke through the minefields on the Sava near Belgrade and pushed upstream to join the fighting near Šabac . In November , French artillery support arrived in Belgrade , endangering the monitor 's anchorage . The stalemate continued until December 1914 when the Serbs briefly evacuated Belgrade in the face of an Austro @-@ Hungarian assault , although Körös did not support this action . After less than two weeks , the Austro @-@ Hungarians had to withdraw from Belgrade , and it was soon recaptured by the Serbs with Russian and French assistance . Körös continued in action against Serbia and her allies at Belgrade until December , when the base of the Danube Flotilla was withdrawn north to Petrovaradin for the winter . 
