The offensive lasted for the next five months and all five AIF divisions in France were engaged in the attempt to stem the tide. By late May the Germans had pushed to within of Paris. During this time the Australians fought at Dernancourt, Morlancourt, Villers-Bretonneux, Hangard Wood, Hazebrouck, and Hamel. At Hamel the commander of the Australian Corps, Monash, successfully used combined arms—including aircraft, artillery and armour—in an attack for the first time. The German offensive ground to a halt in mid-July and a brief lull followed, during which the Australians undertook a series of raids, known as Peaceful Penetrations. The Allies soon launched their own offensive—the Hundred Days Offensive—ultimately ending the war. Beginning on 8 August 1918 the offensive included four Australian divisions striking at Amiens. Using the combined arms techniques developed earlier at Hamel, significant gains were made on what became known as the "Black Day" of the German Army. The offensive continued for four months, and during the Second Battle of the Somme the Australian Corps fought actions at Lihons, Etinehem, Proyart, Chuignes, and Mont St Quentin, before their final engagement of the war on 5 October 1918 at Montbrehain. While these actions were successful, the Australian divisions suffered considerable casualties and by September 1918 the average strength of their infantry battalions was between 300 and 400, which was less than 50 percent of the authorised strength. The AIF was withdrawn for rest and reorganisation following the engagement at Montbrehain; at this time the Australian Corps appeared to be close to breaking as a result of its heavy casualties since August. The Corps was still out of the line when the armistice was declared on 11 November 1918. However, some artillery units continued to support British and American units into November, and the AFC maintained flying operations until the end of the war. Total Australian casualties on the Western Front numbered 181,000, including 46,000 of whom died. Another 114,000 men were wounded, 16,000 gassed, and approximately 3,850 were taken prisoners of war. Small numbers of AIF personnel also served in other theatres. Australian troops from the 1st Australian Wireless Signal Squadron provided communications for British forces during the Mesopotamian Campaign. They participated in a number of battles, including the Battle of Baghdad in March 1917 and the Battle of Ramadi in September that year. Following the Russian Revolution in 1917, the Caucasus Front collapsed, leaving Central Asia open to the Turkish Army.