The Army, throughout the inter-war period, also had to deal with quelling paramilitary organisations seeking the removal of the British. In Iraq, British forces put down the Iraqi revolt of 1920 against British rule in Mandatory Iraq. In British Somaliland, Diiriye Guure's men resumed their campaign against the British, a campaign that had first begun in 1900. The operations against him were prominent due to the newly formed RAF being instrumental in his defeat. The Army also took part in operations in Ireland against the IRA during the Anglo-Irish War. Both sides committed atrocities, some units becoming infamous, such as the paramilitary Black and Tans where many recruits were veterans of the First World War. The British Army was also supporting Indian Army operations in the North-West Frontier of British India against numerous tribes, known collectively as the Pathans, hostile to the British. The Army had been operating in the volatile North-West Frontier area since the mid-19th century. The last major uprising that the Army had to deal with before the start of the Second World War, was the uprising in Palestine that began in 1936.