The city's significance increased as the Ottoman and Russian empires contested its possession. The fortress was stormed by the Russians in the Battle of Kars during the Russo-Turkish War, 1877-78 under generals Loris-Melikov and Ivan Lazarev. Following the war, Kars was transferred to Russia by the Treaty of San Stefano. Kars became the capital of the Kars Oblast (province), comprising the districts of Kars, Ardahan, Kaghisman, and Oltu, which was the most southwesterly extension of the Russian Transcaucasus. In the following years the Russians supported the fortification of Kars.