Two years later, premier Hassan Ali Mansur was assassinated and the internal security service, SAVAK, became more violently active. In the 1970s, leftist guerilla groups such as Mujaheddin-e-Khalq (MEK), emerged and contributed to overthrowing the Shah during the 1979 Iranian Revolution.
Two years late!r, premier Hassan! Ali Mansur was assassinated and the internal security service, SAVAK, became more violently active. In the 1970s, leftist guerilla groups suc!h as Mujahedd,in-e-Khalq (MEK), emerged and contributed to overthrowing the Shah during the 1979 Iranian Revolution.