A long-awaited deal brokered by the United Nations is expected to be signed this week leading to withdrawal of the 115,000 Soviet troops from Afghanistan starting in mid-May. While this development is more than welcome, it does not necessarily mean peace for that divided nation.

Under the terms of the agreement, the first 67,000 Russian soldiers will be pulled out in May, and the rest over a nine-month period. The pullout will mark the first time that Soviet military forces have withdrawn from an occupied country, leaving behind a communist regime that is sure to collapse in their absence.Yet Moscow had little choice. The war was costly and the Soviets discovered what the U.S. already had learned that stubborn, well-armed guerrillas fighting in rugged terrain can frustrate even modern armies that have control of the air. After more than seven years of fighting, Soviet troops were unable to defeat the Moslem rebels, and probably would not be able to do so if the war lasted another seven years.

The pullout likely will not bring peace for a variety of reasons.

First, the staged, nine-month withdrawal of Soviet armies will allow them to continue to prop up the communist government of Afghan President Najibullah. The Russians will continue to supply arms to the regime in Kabul and the U.S. will continue to supply the rebels although the levels of that support have not been clarified.

Second, the Najib government's days seem to be numbered, even with Kremlin supplies. Without the Soviet troops in their way, the guerrillas are expected to take the offensive. U.S. analysts say there is no way the pro-Soviet government will survive.

Third, the expectation of victory likely will make it difficult to draw the rebels into any coalition government. Moscow and neighboring Pakistan want such a government. The Soviets have even recommended a "multi-party system," rather than one-party rule patterned after Russia's.

Apparently the Kremlin figures that even a small slice of the Afghan government would be better than having the communists swept out of office altogether. But the latter seems more likely.

Pakistan wants a coalition government and peace so that the three-million refugees in that country can go home. Another two-million have fled into neighboring Iran.

Fourth, even if the pro-Soviet government falls or becomes a minority shareholder in Kabul, there is potential for conflict among the guerrillas themselves. There are seven different rebel groups with varying philosophies. They have joined forces to fight the Russians and the puppet regime in Kabul. With those foes gone, the guerrillas may turn to fighting each other.

The U.S., as a supplier and backer of the rebels, should use whatever influence it has to work for eventual cooperation and peace in Afghanistan. Let the long-suffering Afghans get on with their lives.