By 9 September, Ukraine had broken through Russian lines, with the Ukrainian military saying that it had advanced nearly 50 kilometres (31 mi) and recaptured over 1,000 square kilometres (390 sq mi) of territory.[56] This advance placed them approximately 44 kilometres (27 mi) northwest of Izium,[57] the main Russian logistics base in the region,[18] a rate of advancement largely unseen since Russia withdrew from Kyiv at the start of the war.[4] The fall of Izium on 10 September was described by The Washington Post as a "stunning rout";[58] the Institute for the Study of War assessed that Ukrainian forces had captured approximately 2,500 square kilometres (970 sq mi) in the breakthrough.[20]