The Action Army, also translated as the Army of Action or Operation Army, was a rebellion force formed by elements of the Ottoman Army sympathetic to the Committee of Union and Progress (CUP) during the 31 March Incident, sometimes referred to as the 1909 countercoup. Mobilised in Selanik by Mahmud Shevket Pasha, it occupied Istanbul and successfully suppressed the uprising in the 31 March Incident.