When the Northwestern Front was split in August, the 10th Army became part of the Western Front, with which it fought for the rest of the war. It fought in the Battle of Vilna between 9 August and 26 September against the German 10th Army. After capturing Kovno on 9 August, the latter attacked between the Viliya and the Neman, attempting to encircle the main forces of the army, concentrated north and northwest of Vilna. In seesaw fighting that lasted until the end of August, both sides suffered heavy losses. The stalemate was broken by the German Sventiany Offensive, beginning on 27 August, which broke through the army defenses and unhinged its rear with a cavalry raid, forcing a retreat to the east. The front stabilized along the line of Lake Naroch and Smorgon by 19 September, after which positional fighting took place.