British war crimes September 1915 and continued their usage for the remainder of the war. This was done in retaliation for the use of chlorine by Imperial German Army the preceding April. Following the Imperial German Army's use of poison gas at Ypres, the commander of II Corps, Lieutenant General Sir Charles Ferguson, had said of poison gas: Mustard gas was first used effectively in World War I by the German army against British and Canadian soldiers near Ypres, Belgium, in 1917 and later also against the French Second Army. The name "Yperite" comes from its usage by the German army near the
Tanks in the German Army I's. By the end of the month, a large portion of the Red Army found itself trapped in the Minsk pocket, and by 21 September Kiev had fallen, thereby allowing the Germans to concentrate on their ultimate objective, Moscow. The StuG III assault gun was used in Operation Barbarossa and was an effective antitank gun in the Panzer Army. Despite the success of Germany's armor in the Soviet Union, between June and September most German officers were shocked to find their tanks were inferior to newer Soviet models, the T-34 and Kliment Voroshilov (KV) series. Army Group North quickly realized