Farther to the north especially heavy fighting occurred for a few days around Skidel, a little town just north of the Niemen on the Grodno-Mosty railroad, and it was not until September 11, 1915, that the Germans succeeded in storming it. On the same day German aeroplanes attacked the important railroad junction at Lida on the Kovno-Vilna railway, and also Vileika on the railway running parallel to and east of the Warsaw-Vilna-Dvinsk-Petrograd railroad. In a way this signified the opening of the German offensive against Vilna. Concurrent with it the fighting on the Dvina between Friedrichstadt and Jacobstadt waxed more furious. Farther south the Germans advanced toward Rakishki on the Kupishki-Dvinsk railroad and between that road and the River Vilia they even reached at some points the Vilna-Dvinsk railroad. Without any lull the battle raged now all along the line from the Dvina to Vilna, and from Vilna to the Niemen. South of this river the attack of the Germans was directed against the Russian front behind the Shara River. By September 14, 1915, Von Hindenburg stood before Dvinsk with one part of his army group. The other parts were rapidly pushing in an easterly direction from Olita and Grodno with the object of attacking Vilna from the south, but they encountered determined resistance, especially in the region to the east of Grodno. With undiminished vigor, however, the Germans continued their advance against Dvinsk and Vilna. To the south of the former city they pushed beyond the Vilna-Petrograd railway, taking Vidsky, just north of the Disna River, in the early morning hours of September 16, 1915. At that time the fall of both Vilna and Dvinsk seemed to be inevitable. On September 18, 1915, the Germans reported continuous progress in their attacks on Dvinsk. On the same day they broke through the Russian front between Vilna and the Niemen in numerous places, capturing over 5,000 men and 16 machine guns. Of railroad lines available to facilitate an eventual Russian retreat from Vilna, the northern route to Petrograd by way of Dvinsk had been in German hands for some days. The southern route by way of Lida to Kovno was imminently threatened at many points. The only other railroad on the eventual line of retreat to the southeast by way of Minsk was likewise threatened both from the south and north. Vilna taken, the Germans immediately bent all their energies to the task of pursuing the retreating Russians.