 However, despite suffering heavily, the mujahideen were able to remain in the field, mostly because they received thousands of new volunteers daily, and continued resisting the Soviets.In an effort to foment unrest and rebellion by the Islamic populations of the Soviet Union, starting in late 1984 Director of CIA William Casey encouraged Mujahedin militants to mount violent sabotage raids inside the Soviet Union, according Robert Gates, Casey's executive assistant and Mohammed Yousef, the Pakistani ISI brigadier general who was the chief for Afghan operations.The rebels began cross-border raids into the Soviet Union in Spring 1985.