On 8 June 1918, the IV Corps entered Tabriz. Yakub Shevki faced an Armenian volunteer force of 4,000 men coming from Van. They aimed to break through the Şahtahtı-Tabriz line and join with Ozanian's forces. On 15 June, the 12th Division of the IV Corps defeated this Armenian unit at a battle to the north of Dilman. The city of Dilman was captured on 18 June. On 24 June, Ozanian's forces managed to defeat opposing units and to lay siege on the city of Khoy. The 12th Division came to the rescue and repulsed Ozanian's forces. At the same time, the 5th Division of the IV Corps had to retreat in the face of a 1,500-strong Armenian force. In the south, Urmia fall to the IV Corps on 31 July. By the end of July, there was an increasing British presence in Persia and the Ninth Army's advance came to a halt.