After the destruction of General Samsonov's 2nd Army in the wake of the Battle of Tannenberg, the 10th Army was formed in late August 1914 from reserve units. On 29 August 1914, Vasily Flug was appointed commander of this 10th Army and made a general of the infantry. Despite successful actions in the battles against the 8th German Army and the taking of Suwałki, and because of disagreements with General Nikolai Ruzsky, Vasily Flug was on 23 September 1914 suspended for "dangerous activities" by the command of the army and transferred to the supreme commander. On 4 October 1914, he was appointed to supervise the restoration of the 13th and 15th Army Corps, which had been all but destroyed in Eastern Prussia in August 1914. On 8 July 1915, he was appointed commander of the 2nd Army Corps. He was awarded the Order of St. George 4th degree.