The Afghan guerrillas, though always in danger of being overwhelmed by the sheer might of the Soviet invaders' military hardware and manpower, have undisguised contempt for the combat prowess of individual Soviet conscripts.

But there is one class of Soviet fighter for whom the mujaheddin have enormous if grudging respect: the special forces, or Spetsnaz. These elite assassins and saboteurs infiltrated Afghanistan before the Red Army trucks rolled across the border in the last days of 1979. They still operate there, doing what they were trained to do: assassinating resistance leaders, laying waste whole villages, striking suddenly like their Afghan adversaries, giving and expecting no quarter.

Spetsnaz killers were "responsible for the assassination of Afghan President {Hafizullah} Amin in December 1979," according to a secret Pentagon briefing paper we obtained. "The most recent and significant employment" of Spetsnaz forces has been to support Soviet operations in Afghanistan since then, it adds.

"Spetsnaz units were deployed to Afghanistan prior to the December 1979 invasion," the briefing document continues. "{Their} presence has provided the Kremlin a key instrument with which to conduct a variety of tactical and strategic operations designed to counter the Islamic insurgency."

There is another arena where Soviet Spetsnaz units operate today -- though less openly. According to the secret briefing paper, Spetsnaz forces are "important instruments for maintaining Communist Party control in the U.S.S.R. and socialist allies of the Warsaw Pact."

When it is understood -- as it surely is in Eastern European capitals -- that Spetsnaz assassination specialists are in place and that they take their orders from the KGB, the ultimate subservience of satellite regimes to Moscow is a foregone conclusion. After all, Afghan President Amin was a Soviet puppet; his only sin was failing to divine his Kremlin masters' desires, and he paid for this error with his life.

Eastern European leaders have an example even closer to home that must be instructive. Spetsnaz troops "played a key role in the 1968 invasion of Czechoslovakia," the Pentagon briefing document points out, explaining: "They seized key governmental facilities, enhancing the movement of Soviet forces in Czechoslovakia."

U.S. intelligence agencies have devoted considerable time and effort to the study of Spetsnaz units, their organization and particularly their missions. According to the Pentagon document, the Soviet Spetsnaz units have five specific wartime assignments:Locate and destroy nuclear weapons. Disrupt command, control, communications and intelligence systems. Disrupt rear-area operations and interfere with supplies and reinforcements. Assassinate or kidnap key military leaders and attack vital units or installations. Provide timely, accurate intelligence, especially early warning of NATO nuclear intentions.