They were indeed left farther from it in the south than in the north. Their defeat east of Vilna enabled Ewarts to escape from the encirclement threatened by the advance from Kovno and Grodno; and although he had to leave Lida and was subsequently pushed behind the junction of Baranowitchi, thus surrendering to the Germans the control of the railway from Vilna to that point, it remained in Russian hands to Rovno. Mackensen was unable to advance from Pinsk, which he occupied on 16 September, to the railway at Luninetz, while Ivanov reacted successfully against the German attacks along the Kovel-Sarny line and recovered a good deal of the ground lost in the Volhynian triangle and eastern extremity of Galicia. Mackensen's army may have been weakened by calls from the north and from the south for a campaign which was already planned but not yet suspected; at any rate it was too weak to achieve its objectives, the capture of Sarny, Rovno, and Tarnopol, which would have completed the hold of the Germans on the Vilna-Kovno line and given them a base for a farther advance in the spring on Odessa and for the isolation of Rumania. On 7 September, as Mackensen's forces were moving on Rovno and the Sereth at Tarnopol and Trembowla, Ivanov counter-attacked from Rovno and Brussilov and Lechitzky on the Sereth. By the 9th the two latter had captured 17,000 prisoners and a considerable number of guns; and Ivanov followed up this success by retaking Lutsk and Dubno by the 23rd. Kovel was even threatened, but the pressure was not maintained. Sarny, Rovno, and Tarnopol were saved, but Lutsk and Dubno reverted to the Germans, and the line in the east was stabilized with the Volhynian triangle and the railway from Vilna to Rovno divided between the antagonists.