On July 15, 1915, the Germans announced that the city of Przasnysz, for which such hot battles had been fought in February, and which had since been strongly fortified by the Russians, had been occupied by them. The German summary of this action given out a few days later stated that three Russian defensive lines lying one behind the other northwest and northeast of Przasnysz had been pierced and taken, the troops at once rushing forward to Dzielin and Lipa, respectively west and east of the town. Under attack from these two points the Russians after yielding Przasnysz, on the 14th, retired to their defensive line Ciechanow-Krasnosielc which had been prepared long beforehand. On the 15th the German troops pressing closer upon the retiring Slavs stormed this line and broke through it to the south of Zielona on a breadth of seven kilometers, forcing the Russians again to retire. General von Gallwitz's troops in this assault were supported by the forces of General von Scholtz, on their left, who were pressing the Russians from the direction of Kolno. On July 16, 1915, the Russians were retreating on the whole front between the Pissa and the Vistula, toward the Narew. The German summary of the fighting during these days reported the capture by the army of General von Gallwitz of eighty-eight officers, 17,500 men, thirteen cannon (including one heavy gun), forty machine guns, and seven mine throwers; and by the army of General von Scholtz of 2,500 prisoners and eight machine guns. This great attack in the north, to which may be ascribed the final breaking of the lines that had so long protected Warsaw, had been carefully planned and undoubtedly was timed in coordination with the movements of Mackensen's armies on the south, striking the Russians just when Mackensen and the Archduke Josef, having had time for recuperation and preparation for another push forward after the check administered at Krasnik, were in readiness to inflict a heavy blow on their side of the Warsaw salient. When it began the German lines all along the front burst into fresh activity. It was the signal for a simultaneous assault along nearly a thousand miles of battle front.