Russian forces continued attacking along the Kupiansk-Svatove-Kreminna line on Dec. 18 as a part of their effort to capture the remainder of Luhansk Oblast and push westward into eastern Kharkiv Oblast, the Institute for the Study of War said in its latest assessment. According to experts, the Russian military is unlikely to have made any significant advances. The ISW points to a Ukrainian General Staff report indicating that Ukrainian forces successfully repelled Russian assaults in various locations, including northeast and east of Kupiansk near Synkivka (nine kilometers northeast of Kupians…