The main Ottoman effort at Baku was assisted by operations on the southern flank, where the 9th Army began an invasion of Iran with six divisions, to capture Tabriz. In late June 1918, two divisions had to be withdrawn but the 12th Division attacked southwards and captured Dilman on 18 June; by 27 July the division had reached Urmia. In late August the advance passed beyond Lake Urmia and to the north, two more Ottoman divisions by-passed Yerevan and went straight toward Nahcivan, which was captured on 19 July. The 11th Division advanced along the railway and captured Tabriz on 23 August, then a force of about advanced on 5 September and drove back Dunsterforce outposts beyond Mianeh and occupied the town, then pressed on to the Persian road near Kazvin. The 39th Infantry Brigade elements diverted from Dunsterforce at Baku to Bijar in August, were organised into Sweet's Column (Lieutenant-Colonel E. H. Sweet) and set off from Hamadan to Zenjan on 14 September, accompanied by an Australian wireless team. The British reinforcements were able to prevent the 9th Army from advancing further and in September, the Ottomans consolidated a line in northern Iran, from Astara on the Caspian Sea south of Baku, to Mianeh in Iran about to the south-east of Tabriz, thence to Sulaymaniyah in Kurdistan.