Massoud's mujahideen attacked the occupying Soviet forces, ambushing Soviet and Afghan communist convoys travelling through the Salang Pass, and causing fuel shortages in Kabul. The Soviets mounted a series of offensives against the Panjshir. Between 1980 and 1985, these offensives were conducted twice a year. Despite engaging more men and hardware on each occasion, the Soviets were unable to defeat Massoud's forces. In 1982, the Soviets began deploying major combat units in the Panjshir, numbering up to 30,000 men. Massoud pulled his troops back into subsidiary valleys, where they occupied fortified positions. When the Soviet columns advanced onto these positions, they fell into ambushes. When the Soviets withdrew, Afghan army garrisons took over their positions. Massoud and his mujahideen forces attacked and recaptured them one by one.