Complex sentence: It is believed, that during the war in Afghanistan, Soviet special forces came in direct conflict with the Pakistan's Special Services Group that was deployed, disguised as Afghans and provided support to the Mujahideen fighting the Soviets.
Split into simpler sentences: It is believed that during the war in Afghanistan, Soviet special forces came in direct conflict with the Pakistan's Special Services Group. This unit was deployed disguised as Afghans, and provided support to the Mujahideen fighting the Soviets.