After their defeat at Sarikamish, the Turks attempted in April of 1915 to turn the extreme left wing of the Russian army by marching to Joulfa through Persia, and from there (in case of success) moving on to Baku, with the hope that the Tartar inhabitants of the eastern Caucasus would immediately join them and enable them to cut the only communicating line of railroad of the Russians, and thereby force the entire Russian army to retreat toward the northern Caucasus. The work of the intelligence department of the Turks was very well organized, especially as the Tartar and Georgian officers of the Caucasus rendered them invaluable services. The Turks knew very well that the Russians in Persia at that time had only one brigade of Russian troops under the command of the Armenian General Nazarbekoff and one battalion of Armenian volunteers scattered throughout Salmast and Urmia, while their own army was made up of one regular and well-drilled division of troops (sent especially from Constantinople) under the command of Khalil Bey and nearly 10,000 Kurds. Khalil Bey with his superior forces captured the city of Urmia in a few hours (taking prisoner nearly a thousand Russians) and victoriously marched on Salmast. Here took place one of the fiercest battles between the Armenians and the Turks. The first battalion of the Armenian volunteers, under the command of the veteran Andranik, strongly enforced in its trenches, repulsed the attacks of Khalil Bey for three days continuously, until the Russians, with the newly-arrived forces from the Caucasus, were able to put to flight the army of Khalil Bey. Thirty-six hundred Turkish soldiers lay dead before the Armenian trenches in the course of those three days.