In early 1944, the 509th was involved in the Second Battle of Kiev and then retreated across Ukraine. In late May, the depleted 509th was pulled back for refitting. After receiving a full complement of Tiger 1s, the battalion was sent back to the front on 1 June 1944. On 22 June 1944, the Red Army launched Operation Bagration, and the 509th, attached to Army Group Centre, was in their line of advance. On 8 September 1944, the detachment lost sixteen Tigers in under 24 hours near Kielce, Poland.