 During this offensive, to avoid losing vehicles to land mines, the Soviets sent their sapper units to clear the way in front of the main force.This tactic proved costly, and the attack force penetrated only 25 km into the valley before retiring, after having suffered 100 casualties.By 1982 Massoud had built up his forces to 3,000 men, and other Mujahideen from neighbouring areas could come to his aid The approaches to the valley were strengthened with defensive positions established on dominant heights and near narrow passages.