 Lead elements of two Polish divisions from the 1st Army attempted to cross the Vistula into Warsaw on 13 September but made little progress and having sustained heavy casualties were evacuated back across the river ten days later.The Uprising forces capitulated on 2 October; the Soviets would take Warsaw without a major battle during their advance early in 1945.American military historian David M. Glantz notes that while the Soviets could have taken Warsaw and aided the insurgents, from a purely military standpoint this would have required diverting efforts from attempts to secure bridgeheads south and north of Warsaw, involved the Soviets in costly city fighting and gained them less optimal positions for further offensives; this, coupled with political factors meant that the Soviet decision not to aid the Warsaw Uprising was based not only on political, but also on military considerations.