On February 23, 1917, the Russian advance was halted following the Russian Revolution, and later the disintegrated Russian Caucasus Army was replaced by the forces of the newly established Armenian state, comprised from the previous Armenian volunteer units and the Armenian irregular units. During 1918 the region also saw the establishment of the Central Caspian Dictatorship, the Republic of Mountainous Armenia and an Allied force named Dunsterforce which was composed of elite troops drawn from the Mesopotamian and Western Fronts. The Ottoman Empire and German Empire had a hot conflict at Batumi with the arrival of German Caucasus Expedition whose prime aim was to secure oil supplies.