In 1953 the CIA, working with the British government, initiated "Operation Ajax" against the Prime Minister of Iran Mohammad Mossadegh who had attempted to nationalize Iran's oil, threatening the interests of the Anglo-Persian Oil Company. This had the effect of restoring and strengthening the authoritarian monarchical reign of Shah Mohammad Reza Pahlavi. In 1957, the CIA and Israeli Mossad aided the Iranian government in establishing its intelligence service, SAVAK, later blamed for the torture and execution of the regime's opponents.