 On April 22, after a two-day bombardment of the region by Tu-16, Tu-22M and Su-24 bombers, they advanced rapidly into the Panjshir.Several battalion strength forces were placed at key passes leading out of the Panjshir Valley while at the same time large helicopter troop landings were made in tributary valleys connected to the Panjshir.By blocking the Mujahideen's withdrawal routes and securing the high ground, the Soviets forced them higher into the mountains then they had previously ventured and scattered their strength as they attempted to avoid being trapped by the helicopter landings.