Washington — The Soviet escalation of the war in Afghanistan is seen here as a reaction to the increased effectiveness of the Afghan guerrillas. The escalation appears to reflect as well a failure on the part of the Soviets to build a more effective Afghan force of their own.
The forces spearheading the current offensive into the strategic Panjshir Valley are reported to be Soviet, with Afghan government forces playing only a supporting role.
The escalation of the fighting, which includes for the first time the heavy use of high-altitude bombing by Soviet planes, may also mean that the Soviets see little chance of an improvement in East-West relations this year, or at least before the American presidential elections in November. The Soviets may believe that they have little to lose for the moment from sharply escalating the war, according to some specialists on Soviet affairs.
''This has to be labeled speculation,'' says Dimitri K. Simes, a specialist at the Carnegie Endowment for International Peace, ''but I begin to see a pattern of Soviet assertiveness - cautious assertiveness - in a number of areas. The Soviets seem to be trying to prove that they have options other than negotiating.''
Dr. Simes was referring in part to recently conducted Soviet naval maneuvers in the Norwegian Sea, a largely symbolic but increased Soviet naval presence in the Caribbean, Soviet air maneuvers that created problems in the Berlin air corridor, and the current Soviet air and land offensive in Afghanistan.
During the last big attacks into the Panjshir, in May and September of 1982, the Soviets succeeded in occupying most of the valley, but they failed to break the resistance. This time the Soviets appear to be determined to destroy the forces of the man reputed to be the most effective of the guerrilla leaders, a young Tajik named Ahmad Massoud.
In January 1983, Mr. Massoud accepted a Soviet proposal for a cease-fire and used the respite to regroup and rebuild his forces. He also met with resistance commanders from six provinces to discuss more effective guerrilla cooperation.
State Department officials say they are not surprised by reports from the Afghan government radio that Massoud's forces have been driven from the Panjshir Valley as a result of the current offensive. The pattern in past offensives has been for the Soviets to move up the entire valley floor.
Seeing the many signs of the Soviet attack in advance, the guerrillas are reported to have begun evacuating people from the valley for some weeks now. The typical pattern has been for guerrillas to retreat from large Soviet units and then to launch hit-and-run raids on the Soviets. As one State Department official put it, ''The Soviets may occupy the valley, but the battle has not yet begun.''
The 70-mile-long valley has been used as a base for guerrillas attacking the main highway linking the capital city of Kabul with the Soviet Union. Guerrilla attacks against fuel convoys have resulted in severe petroleum shortages in Kabul. According to State Department spokesman Alan Romberg, the resistance fighters have destroyed several important bridges, further complicating the effort to keep Kabul supplied with fuel.
Mr. Romberg said it appeared that the Soviets began to bomb up and down the Panjshir Valley on April 19-20. Defense Department spokesman Michael Burch said that the Soviets appeared to be using medium-range TU-16 ''Badger'' bombers in their offensive.
Romberg said that a large convoy of Soviet military vehicles were seen moving from the south of the Panjshir Valley to the north. But the Soviet offensive is not limited to the valley. Officials say that the Soviets have launched additional major attacks in several other parts of the country.
''The new elements this year are high-altitude saturation bombing by the Soviets and the presence of such large forces,'' Rombergsaid. He described the offensive as an ''escalation of the destructive and brutal anticivilian Soviet warfare in Afghanistan.''
In Winter 1983-84 edition of the magazine Foreign Affairs, Claude Malhuret, executive director of the Paris-based Medecins sans Frontiers - Doctors Without Borders - which maintains medical teams in Afghanistan, wrote that the Soviets may have turned increasingly to the use of air power because of losses inflicted on their ground troops. Dr. Malhuret said that one of the main aims of Soviet air attacks was not strictly military victory but to impose a ''reign of terror.''
It is widely assumed here that the Afghan guerrillas, or mujahideen, receive some forms of covert assistance from the United States, China, and a number of Islamic nations. But the guerrillas constantly complain of a lack of adequate weapons and vulnerability to air attacks, particularly from Soviet helicopter gunships. Despite their lack of sophisticated antiaircraft weapons, however, the guerrillas are reported to have downed more Soviet helicopters over the past year than they had in the previous year.