In Mesopotamia British troops continued to pursue the Turks on both banks of the Tigris. On October 25, 1918, British columns moving up the eastern bank forced the passage of the Lesser Zab near its mouth in conjunction with cavalry, which had crossed this river on the previous evening seven miles farther upstream. The latter movement turned the left flank of a Turkish force holding the angle formed by the junction of the Lesser Zab with the Tigris, and assisted the main body to drive the enemy across the Tigris to the western bank. Meanwhile other British troops advancing up the right on western bank of the Tigris over a difficult country, much cut up by ravines, forced the Turks from a hill position which they were holding in prolongation of their forces on the left bank. The enemy, after burning their stores, retired about four miles farther up the river. On the Kirkuk road, the main Bagdad-Mosul highway, lying east of the Tigris, British patrols entered the southern outskirts of Kirkuk. The Turks appear to be occupying in strength the high ground to the north of the town, which is about 100 miles southeast of Mosul. On October 26, 1918, the Turks still held a strong position on the Jebel Hamrin, west of the mouth of the Lesser Zab. But on the previous day British armored cars, moving by the desert track farther to the west, had struck in on the Turkish line of communications in the neighborhood of Kalet Shergat, where they attacked the enemy's convoys. At the same time British cavalry, moving up the left bank of the Tigris, threatened the enemy's line of communication from the east. The pressure of British troops in front, combined with attacks on their communications, compelled the Turks to retreat twelve miles to the north during the night of October 26, 1918, to a position three miles south of Kalet Shergat. By October 27, 1918, the British main body was in touch with Turkish troops covering the crossing of the Lesser Zab. All that day Turkish reserves tried to break through the Eleventh Indian Cavalry Brigade, who barred the road to Mosul, but without success, though the arrival of Turkish reenforcements from Mosul forced that brigade to draw back its right in order to cover its rear. On the night of October 27-28, 1918, the Seventh Indian Cavalry Brigade joined the Eleventh, and the Fifty-third Indian Infantry Brigade, moving up the east bank after a march of thirty-three miles, was able to support the cavalry in preventing any Turks from breaking through northward. On October 28, 1918, the Seventeenth Indian Division successfully assaulted the Turkish Shergat position, and on the 29th, though exhausted by their continuous fighting and marching through the rugged hills, pushed forward and attacked till nightfall the Turks who were now hemmed in.